In the title compound, C(23)H(19)N(3)O(2), the dihedral angles formed by the pyrazolone ring with the three benzene rings are 30.91 (6), 60.96 (4) and 57.01 (4)°. The ligand is in the enamine-keto form and its structure is stabilized by an intra-molecular N-H⋯O hydrogen bond. In the crystal, O-H⋯N hydrogen bonds link mol-ecules into chains parallel to [01-1].