Abstract The bicyclic 2, 3, 3a, 4-tetrahydro-1H-imidazo [5, 1-c][1, 4] benzoxazin-1-one system and the related 1, 4-benzo-thiazine and 4, 1] benzoxazepine analogs were synthesized. They were easily obtained by melting a suitable diamine derivative with urea. Some of them displayed very good reversible MAO-I activity selective for type A. The preparation of the intermediate amines is also given.