He has been conducting research on molecular photoswitches (photochromic molecular systems) for the last 40 years.　In the middle of the 1980s he discovered a new class of photochromic molecules, DIARYLETHENES , which undergo thermally irreversible and fatigue resistant photochromic reactions.　 At present, these derivatives are widely used in functional molecular systems as key elements of photoswitches.　He has received the following awards: Award of the Society of Polymer Science, Japan (1988), Award of the Japanese Photochemical Association (1993), Vinci d'Excellence (LVMH, France, 1995), Docteur Honoris Causa of University of Bordeaux I (2003), The Chemical Society of Japan Award (2004), Mukai Award(2007), The Purple Ribbon Medal (2007), Theodor-Förester-Preis (GDCh and Deutsche Bunsen-Gesellschaft für Phys. Chem., Germany, 2008) and The Porter Medal (European Photochemistry Association, The Inter-American Photochemistry Society and The Asian and Oceanian Photochemistry Association, 2014).