4-Methyl-5-phenyl-1H-pyrazol-3(2H)-one

The asymmetric unit of the title compound, C(10)H(10)N(2)O, contains two crystallographically independent mol­ecules with similar geometries, which exist in the keto form. The C=O bond lengths are 1.2878 (12) Å in mol­ecule A and 1.2890 (12) Å in mol­ecule B, indicating that the compound undergoes enol-to-keto tautomerism during the crystallization process. In mol­ecule A, the pyrazole ring is approximately planar [maximum deviation = 0.007 (1) Å] and forms a dihedral angle of 36.67 (6)° with the attached phenyl ring. In mol­ecule B, the dihedral angle formed between the pyrazole ring [maximum deviation = 0.017 (1) Å] and the phenyl ring is 41.19 (6)°. In the crystal, inter­molecular N—H⋯O hydrogen bonds link neighbouring mol­ecules into dimers generating R (2) (2)(8) ring motifs. These dimers are linked into ribbons along [101] via inter­molecular N—H⋯O hydrogen bonds, forming R (4) (2)(10) ring motifs.