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.<!?tpb=22pt>