3a-Phenyl-2,3,3a,4-tetrahydro-1H-benzo[d]pyrrolo[1,2-a]imidazol-1-one, a potential plant-growth regulator.

Molecules of the title compound, C₁₆H₁₄N₂O, a potential plant-growth regulator, are linked into chains by intermolecular C=O∙∙∙H-N hydrogen bonds. These chains are weakly interconnected by π-π stacking interactions to form a three-dimensional framework. A comparison of the geometric parameters of the title molecule and several related benzimidazoles and pyrrolidones is presented.