4-Phenyl-1H-1,5-benzodiazepin-2(3H)-one.

In the title compound, C15H12N2O, the phenyl ring makes a dihedral angle of 32.45 (9)° with the benzene ring of the 1,5-benzodiazepin-2-one unit. The seven-membered ring adopts a boat conformation with the methyl-ene group as the prow and the fused benzene-ring C atoms as the stern. In the crystal, inversion dimers linked by pairs of N-H⋯O hydrogen bonds generate R2(2)(8) loops. The dimers are further linked by C-H⋯O hydrogen bonds, so forming a column along the a-axis direction.