Abstract
The mechanism of photoisomerization of diarylethenes is considered, including its multiplet, conformational and energetic aspects. The experimental data on the "one bond flip" and "hula-twist" photoisomerization mechanisms, the adiabatic and diabatic reaction channels and also on one-photon photocyclization of diarylethylene trans-isomers are surveyed. The results of quantum chemical calculations of the potential energy surface along the reaction coordinates of diarylethylene isomerization and cyclization are analyzed. The bibliography includes 179 references.