4-[(Z)-Allyl-amino-(phen-yl)methyl-ene]-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one.

The title compound, C20H19N3O, exists in a keto–enamine tautomeric form. The pyrazolone ring makes dihedral angles of 20.52 (10) and 77.73 (5)° with the two phenyl rings and an intra­molecular N—H⋯O hydrogen bond occurs. A weak inter­molecular C—H⋯O hydrogen bond is observed in the crystal structure. The allyl group is disordered over two positions, with site-occupancy factors of 0.533 (5) and 0.467 (5).