A synthetic approach to the previously unknown 3a,4,5, 6-tetrahydro-3H[1,2,4]triazolo[4,3-a][1,5]benzodiazepine system via [3 + 2]-cycloaddition of nitrile imines to 2, 3-dihydro-1H-1,5-benzodiazepines is described. In an analogous way, the 3 a,4,4a,5-tetrahydro-3H-bis[1,2,4]triazolo [4,3-a:3′,4′-d][1,5]benzodiazepine system is prepared from 3H-1,5-benzodiazepines.