Novel 1-substituted benzodiazepine derivatives and salt thereof having the formula, ##STR1## wherein R.sub.1 is a hydrogen atom, a halogen atom, a nitro group, a cyano group, a lower alkoxy group or a trifluoromethyl group; R.sub.2 is a pyridyl group or a group of the formula ##STR2## wherein R.sub.5 and R.sub.6 represent individually a hydrogen atom, a halogen atom, a lower alkyl group or a trifluoromethyl group); R.sub.3 is a hydrogen atom or a lower alkyl group; R.sub.4 is a lower alkyl, cycloalkyl, cycloalkylalkyl, aryl or aralkyl group; m is 1 or 2; and n is an integer of 1 to 4, and a process for preparation thereof and pharmaceutical use of the same.The benzodiazepine derivatives are effective as tranquillizers, muscle-relaxants and hypnotics.