In the solid state, the title compound, C20H19N3O2, adopts the keto–amine tautomeric form, with the H atom attached to the N atom, which participates in an intramolecular N—H...O hydrogen bond with an S(6) ring motif. The dihedral angles between the pyrazole ring and the phenyl and benzene rings are 3.69 (10) and 46.47 (9)°, respectively. In the crystal, molecules are linked by weak C—H...O hydrogen bonds, generating C(16) chains propagating in [301]. Weak aromatic π–π stacking interactions [centroid–centroid distances = 3.6123 (10) and 3.6665 (10) Å] link the chains into a three-dimensional network.