Efficient one pot synthesis of [1,2,4]triazolo[4,3-α][1,4]benzodiazepines derivatives. chloro-6- phenyl-1-(substituted)-4H-[1,2,4]triazolo[4,3-α][1,4]benzodiazepine were efficiently synthesized by oxidative cyclization reaction of 2-hydrazino-1,4-benzodiazepines with various aldehydes in presence of diacetoxy iodobenzene.