7-Chloro-5-cyclo-propyl-9-methyl-5H-4,5,6,10-tetra-aza-dibenzo[a,d]cyclo-hepten-11(10H)-one.

In the title compound, C(15)H(13)ClN(4)O, which is a chloro derivative of the drug Nevirapine, the diazepine ring is in a twisted boat conformation. The pyridine rings fused to the diazepine fragment form a dihedral angle of 58.44 (10)° and the mol-ecule adopts a butterfly shape. The mol-ecules are joined via N-H⋯N hydrogen bonding into polymeric chains down the b axis. All weaker C-H⋯O inter-actions involve the carbonyl O atom as acceptor.