New phenazine-based photosensitizers with extended conjugation and different functional groups were developed, and their photophysical properties and photosensitizing abilities to produce singlet oxygen were investigated.

Molecular photoswitches have been widely used as molecular machines in various fields due to the small structures and simple motions generated in reversible isomerization. However, common photoswitches, as represented by azobenzene (AB), cannot combine both large motions and high thermal stability, which are critically important for some practical applications in addition to high photoisomerization yields. Here, we focus on a promising photoswitch, stiff stilbene (SS), and its derivative, sterically hindered SS (HSS). The detailed investigation of their performance with a comparison to AB demonstrated that HSS is an outstanding photoswitch offering larger motions than AB and SS, ca. 90% photoisomerization in both E-to-Z and Z-to-E directions, and significantly high thermal stability with a half-life of ca. 1000 years at room temperature. The superior performance of HSS promises its use in various applications, even where previous photoswitches have troubles and are unavailable.

Fluorescent sensors DJ-1 and DJ-2 with a large Stokes shift (SS) based on a combination of photo-induced electron transfer (PET) and Förster resonance energy transfer (FRET) for the detection of water in solvents have been developed.