A synthetic approach to new 11H-tetrazolo[1,5-c][2,3]benzodiazepine derivatives starting from 3,5-dihydro-4H-2,3-benzodiazepin-4-ones is described. The structural features of compounds obtained were ascertained by NMR spectroscopy. The proton and carbon assignments were made with the aid of two-dimensional heteronuclear chemical shift-correlation experiments.