A new diarylethene-derived photochromic compound, with little cytotoxicity, plasma membrane-permeability, and efficient photoswitchability in cells upon alternative UV and visible light irradiation, was synthesized and applied to live cell imaging.

a series of diarylethene compounds with a thiophene bridging unit have been synthesized to investigate the relationship between molecular structure and photochromic properties. In particular, the fluorescence properties related to compound 1 were investigated. The results showed that a six-membered ring carrying an electron-donating sulfur atom and an electron-withdrawing carbonyl group is necessary to form a "push-pull" system for the fluorescence of 1.