Solid-state photoreactions of S-(o-tolyl), S-phenyl, and S-(m-tolyl) 2-benzoylbenzothioates, which formed chiral crystals by spontaneous resolution, underwent an unprecedented intramolecular cyclization involving phenyl migration to afford optically active corresponding 3-phenyl-3-(arylthio) phthalide in good chemo-and enantioselectivities. Stereochemical assignment and substituent probe experiment of this photoreaction sequence led to a ...