Irradiation of the 2-methylquinoline N-ethoxycarbonylimides (15a-d) having an electron-donating substituent in the 6- or 8-position gave the novel 3H-1, 3-benzodiazepines (16), together with the parent quinolines (13), whereas substituted quinoline N-imides having either an electron-donating or-withdrawing group in other positions gave no benzodiazepines. These substituent effects are discussed. A similar substituent effect was also observed in the photo-induced rearrangement of the isoquinoline N-ethoxycar-bonylimides (25) to the 1H-1, 3-benzodiazepines (28).