Crystal structure of (4Z)-4-[(2E)-1-hydroxy-3-(naphthalen-2-yl)prop-2-en-1-yl-idene]-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one.

In the title compound, C23H18N2O2, the pyrazole ring subtends dihedral angles of 2.01 (13) and 1.55 (10)° with the pendant benzene ring and the naphthalene ring system, respectively. The mol-ecule is almost planar (r.m.s. deviation for the 27 non-H atoms = 0.025 Å) and intra-molecular O-H⋯O and C-H⋯O hydrogen bonds both close S(6) loops. In the crystal, very weak aromatic π-π stacking inter-actions between the benzene and the pyrazole rings, with centroid-centroid distances of 3.8913 (14) and 3.9285 (15) Å, are observed.