Diarylethenes having thiazole rings, 1, 2-bis (thiazol-4′-yl) perfluorocyclopentenes and 1, 2- bis (thiazol-5′-yl) perfluorocyclopentenes, were synthesized. The binding positions of the thiazole rings to the perfluorocyclopentene moiety strongly affected the absorption spectra. The absorption maxima of the open-and closed-ring forms of 1, 2-bis (5′-methyl-2′- phenylthiazol-4′-yl) perfluorocyclopentene were observed at 300 nm and 525 nm, ...