The title compound, C(12)H(11)BrN(2)O(2), was prepared by an intra-cyclization reaction of (S)-1-(5-bromo-2-nitro-benz-yl)-5-oxopyrrolidine-2-carb-oxy-lic acid methyl ester in the presence of EtOH/Fe. The five-membered pyrrolidinone ring adopts an approximate envelope conformation, while the seven-membered diazepanone ring displays a twisted boat conformation. Inter-molecular classical N-H⋯O hydrogen bonds and weak C-H⋯O inter-actions help to stabilize the crystal structure.