Photolysis of two S-Ph thiobenzoates with a different substituent groups in benzene ring. was studied in solution and on thin-layer chromatog. plates. It was found that the photolytic products of S-Ph thiobenzoate include benzaldehyde, thiophenol, diphenyldisulfide, diphenylsulfide, 1,1'-biphenyl and two photo-Fries rearrangement products ortho-mercaptobenzoylbenzene and para-mercaptobenzoylbenzene. Results indicate that the distribution of photolytic products strongly depends on the environmental medium. Cage effect and external magnetic field effect both which played and important role in the photolysis of these compounds are also discussed. It was further confirmed that the photolytic reaction of S-Ph thiobenzoates proceeds through the triplet excited state

Key words: BIPHENYL, DIPHENYLMETHANONE P, BENZENECARBOXYLIC ACID P, DISULFIDE, BENZALDEHYDE, BENZENETHIOL, THIO ACID, PHOTOLYSIS