Imagine a crystal that breathes. Sounds like science fiction, right? But that’s exactly the kind of enchantment Japanese chemist Susumu Kitagawa has been chasing—creating materials that flex, open, and trap gases like tiny molecular hotels. Welcome to the fascinating world of Susumu Kitagawa.
A Spark in Kyoto: Who Is Susumu Kitagawa?
Born on July 4, 1951, in Kyoto, Japan, Kitagawa trained and stayed close to home—earning his degrees at Kyoto University.
He rose through academic ranks and co-founded the Institute for Integrated Cell-Material Sciences (iCeMS) at Kyoto, where he remains a distinguished professor.
Kitagawa isn’t just any chemist—he’s one of the key architects behind the field of metal-organic frameworks (MOFs), also known as porous coordination polymers (PCPs).
In 2025, he was awarded the Nobel Prize in Chemistry for his pioneering work in developing MOFs.
What Are MOFs—and Why They Matter
At first glance, MOFs might sound like jargon. But think of them as molecular scaffolding: metal atoms act like nodes, organic molecules act like connectors, and together they form a network with internal cavities. Those cavities can trap, release, or sort small molecules.
Here’s what makes MOFs exciting:
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High surface area: A small amount of MOF can have more internal surface space than you’d ever imagine.
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Selective capture: Depending on their structure, MOFs can target specific gases like CO₂, hydrogen, or methane.
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Adjustable flexibility: Some MOFs bend or flex in response to the molecules passing through—unlike rigid traditional porous materials.
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Functionalization: You can attach chemical groups to the internal walls to tweak how the material interacts with its guests.
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Applications everywhere: gas storage, catalysis, pollution control, and even water harvesting in deserts.
Kitagawa’s contributions centered on two bold ideas: introducing porosity into coordination networks and making those networks flexible and responsive.
Susumu Kitagawa’s Signature Moves in MOF Chemistry
Demonstrating Porosity in Coordination Complexes
Before Kitagawa, coordination polymers and complexes were largely thought to be dense, static arrangements. In 1997, he and colleagues proved that certain coordination compounds could have measurable porosity through gas adsorption experiments.
This shifted scientific thinking: crystals need not be impermeable solids—they could host internal space. That was a conceptual leap.
Proposing the “Chemistry of Coordination Space”
Kitagawa coined the phrase “chemistry of coordination space”—an approach that treats internal nanoscale voids as a design feature rather than an absence.
Instead of viewing space as “nothing,” he asked: how can we control that nothing to do something useful?
Flexible, Soft Porous Crystals
One of his landmark contributions was the discovery of MOFs (or PCPs) that respond to stimuli—temperature, pressure, or guest molecules—by bending or rearranging. These are often called “soft porous crystals” or flexible MOFs.
Imagine a sponge that changes shape depending on what it’s soaking up—MOFs like that open new possibilities for “smart” materials.
Pushing Gas Sorption and Molecular Gatekeeping
In some of Kitagawa’s later work, gas sorption becomes self-accelerating—as a gas enters the MOF, the structure adapts to make more room.
He and his team also studied how molecules travel through narrow MOF channels, squeezing through tight spots with astonishing precision.
Philosophical Backbone: “Usefulness of Useless”
Kitagawa often cites his guiding philosophy: find the usefulness of useless.
He draws inspiration from philosophy and literature, believing that even abstract ideas—like empty space inside a crystal—can have practical power.
To him, the beauty of science lies in uncovering hidden potential within the invisible.
5 Surprising Facts About Kitagawa & His Work
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He has published over 600 research papers and is among the most cited scientists in materials chemistry.
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In 2023, he was elected a Foreign Member of the Royal Society in the UK.
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Despite working in the invisible nanoscale world, Kitagawa enjoys detective fiction, kabuki theater, and European thriller films.
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His work laid the groundwork for MOF-based technologies that could someday help remove CO₂ from the atmosphere, store hydrogen fuel, or clean polluted water.
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His 2025 Nobel Prize was shared with Richard Robson and Omar Yaghi, recognizing decades of collaborative innovation in molecular frameworks.
Susumu Kitagawa: A Heading for New Material Horizons
Kitagawa’s life is a testament to how curiosity at the micro scale can ripple out into macro implications. His approach shows that the spaces between molecules can be just as rich as the molecules themselves.
He tackles global challenges—energy, sustainability, environment—by tinkering with the nanoscale. It’s a reminder that even in science, shifting perspective can reveal new worlds. Treat the invisible not as void, but as potential.
I find this deeply inspiring. When I first learned about MOFs, I remember wondering: how do you see a hole? Kitagawa’s work taught me that holes can behave—they can trap, flex, and even breathe.
Personal Insight
When writing this, I felt a little thrill imagining a crystal structure that adjusts itself as gas molecules enter—like a hidden organism breathing. I’m also humbled that such profound ideas come not from bigger machines or louder experiments, but from a refined understanding of space, structure, and imagination.
In my own work, I’ve often brushed off abstract ideas as impractical—but Kitagawa’s journey reminds me that the abstract often becomes the most transformative.
Conclusion
Susumu Kitagawa transformed how scientists think about the unseen interiors of materials, pioneering MOFs and introducing the “chemistry of coordination space.” His work bridges art, science, and philosophy—turning emptiness into innovation and earning him the Nobel Prize in Chemistry.
Which part of Kitagawa’s story fascinates you most—the flexible crystals, the gas-trapping potential, or the idea that even “nothing” can be useful? Share your thoughts below!