Interview with the 2025 Nobel Prize laureate in chemistry Susumu Kitagawa on 6 December 2025 during Nobel Week in Stockholm, Sweden.

How did you become interested in science? 

Susumu Kitagawa: I was born in Kyoto and I graduated from Kyoto University. I enjoyed very much my life in Kyoto, because Kyoto is a 1,200-years-old capital. There are many cultures, particularly in the historical books. My background is that everything changes. This is very important, and this notion shaped my research to the material chemistry. When I was an elementary school student, I read a lot of autobiography of scientists; Pasteur, Hideyo Noguchi, a Japanese physiologist, and Einstein and so on and so forth. Maybe these books made me interested in science. 

What sort of child were you? 

Susumu Kitagawa: My childhood, and in particular in elementary school, I was very active, just playing games and playing baseball with my friends. That was a very nice time. 

In junior high school, I started to understand mathematics and science. I got interested because in the first year, the first day, there were two friends and the one guy, he read all textbooks of mathematics. First day of the first year! He was so fantastic. I learn from him. I studied by myself, not received from the teachers saying something. The other guy, he read a lot of novels, in particular science fiction. He introduced many books, and I read them. It was so nice for my imagination; the science in the future.  

And I played volleyball. I belonged to a club. From the early morning to the evening, every day. It was so good for my future shape. The health is very important in the research, particularly in chemistry. 

Was there a teacher who influenced you? 

Susumu Kitagawa: In high school, I learned Greek philosophy. That teacher was very nice. He introduced, for instance, the Heraclitus. Heraclitus said “panta rhei,” everything changes. We cannot step into the same river twice. That, as I told you in the beginning, had a very, very strong impression on me. Now in my chemistry, I introduce this concept in my compounds. 

Have any Nobel Prize laureates influenced you? 

Susumu Kitagawa: I have to tell you the story of Kyoto University, and the first Nobel laureate professor Yukawa in physics. He loved to read Zhuang Zhou. Zhuang Zhou is the ancient philosopher. 2,400 years ago, he said, “usefulness of the useless.” I read professor Yukawa’s book and I learned a lot. This was the first Nobel laureate in Kyoto University. But I entered Kyoto University and there is a department, where another is a Nobel laureate, professor Fukui, the chemistry Nobel laureate. In the graduate course I belonged to his sister laboratory and my senior was dr Yoshino. He also won the Nobel Prize. So in the same laboratory, already two Nobel laureates. I was so influenced by their attitude for science. The atmosphere and scientific atmosphere in that laboratory is very free. I mean, freedom, that is very important. Even to the professor we could say, “I think this is good” or something like that, and the professor did not say, “No, you should not do so.” They say, “Okay, if so, do it.” That’s a very nice science atmosphere. 

Can you explain the notion “the usefulness of useless?” 

Susumu Kitagawa: After my graduation from Kyoto University, I got the job as the assistant professor in the Kindai University where Professor Munakata carried out Copper(I) chemistry. The copper materials that surround you, that is Copper(II) Plus – oxidised form. Copper(I) we rarely see. So that means Copper(I) looks like it’s useless. However, in the Kindai University, I carried out Copper(I) chemistry and Copper(I) gives a very beautiful crystal structure, sometimes a network structure. Richard Robson, the other laureate in chemistry, he carried out Copper(I) chemistry and got beautiful diamond-like structure. And Omar Yaghi. So Copper(I) is a sort of a useful metal ion. It looks useless, but ultimately it’s useful. 

So, Zhuang Zhou’s notion is very, very effective. The usefulness of useful, that means something already exists. This is a kind of follower of a pioneer. But useless things are considered “no way.” You are focusing on and carrying out this kind of science. But if you do another side and then create new things, in the future, you’ll be a pioneer. So this is the usefulness of the useless. It’s a sort of creativity. 

What qualities are important in a scientist? 

Susumu Kitagawa: If a researcher is doing a very new idea, it’s very difficult to get research funds. So one thing is to be very patient. I usually tell young people, that there is a Japanese-Chinese character: Un Don Kon. “Un” is fortune or luck. Louis Pasteur said, “Fortune favours the prepared mind.” Just as I said, in junior high school and in school, I got many advice and notions. This gives a prepared mind. 

“Don” means a kind of insensitiveness, being less sensitive. If scientists show a very nice theory or material, the young people, if they are smart, quickly understand. That means they follow this chemistry or science. But insensiveness means, don’t just accept this. Think. Deep think about it and then take action.  

Lastly, “Kon” means never give up. These three factors are very important. Of course, in the last one, patience is very important. So if you cannot get research funds, think of something to survive with this idea for 10 years or so. This is my history. 

What makes for a good research environment? 

Susumu Kitagawa: In my laboratory, I follow Professor Fukui’s laboratory’s atmosphere. If the postdocs and students say, “We can do it”, but I think, “It’s not very interesting,” still, I say, “Okay, you can do it.” For instance, the student got some data, and it’s not so good data, I say “Okay, you can do it”, but ultimately, “Show me the results.” This is a kind of freedom. Most of the professors say, “oh, no, you cannot do so.” This attitude is not good for the fundamental science. In my laboratory, I organise the laboratory at any time. That kind of freedom is very important. 

What do you think makes a good research leader? 

Susumu Kitagawa: I told you when I was junior high school student, I played volleyball. Volleyball is a group play, and I was captain for two years. So I know how to organise people. This experience is very important for my research; group organisation. A good leader respects their capability.  Also, communication is very important. 

Do you enjoy teaching young people? 

Susumu Kitagawa: I really enjoy the discussions with young people. Teaching is mostly one way. I like it, but not so strongly. But the discussion is both directions, the communication. I like it this way. 

What advice would you give a young scientist? 

Susumu Kitagawa: Just one thing; don’t follow the existing research. Think for yourself. That’s very important. Another thing I have to say is, if you want to be a great scientist, you have to see others, discuss. Recognise that this is a great scientist. This is my advice. 

How important is it to use your research to solve global challenges? 

Susumu Kitagawa: In my chemistry, our target is gas substances. In the 19th century, people used coal as energy resource, and during the 20th century is was petroleum and underground resources. But now, in the 21st century, it’s a big concern about the global warming and the shortage of underground resources. So instead, we have to think what is best for the future, and that’s the gas substances. So this target is very important, not only for myself but also for young people. I wish they do this kind of advanced science and technology for the future. 

What do you like doing in your spare time? 

Susumu Kitagawa: Reading a book. In particular, detectives and police stories or something. And of course, science fiction. 

How do you make time for yourself? 

Susumu Kitagawa: Every day I commute by train. There is the express and the local train. I like the local train. I find my seat and for almost 40-45 minutes, I can read a draft, or a collaborator’s paper or other papers. Yeah, it’s a very, very happy time because nobody disturbs me. In the laboratory and in my office, several people come. There is always something.  

Watch the interview