Abstract This article presents a synthetic method and reaction mechanism of the 1, 5- benzothiazepines and 1, 5-benzodiazepines derivatives. In this research, 36 thiazepines and diazepines (mostly new) with a new method have been prepared and their structures have been characterized by spectroscopic methods. Crystal structures of a new thiazepine and diazepine (seven-membered rings) have also been determined and compared with ...