(E)-5-(4-Methyl-benzyl-idene)-1-phenyl-4,5,6,7-tetra-hydro-1H-indazol-4-one.

In the title compound, C21H18N2O, the non-aromatic six-membered ring adopts a distorted envelope conformation with one of the methyl-ene-C atoms being the flap atom. The dihedral angle between the phenyl and 4-tolyl rings is 75.3 (1)°. The 1,2-diazole ring forms dihedral angles of 41.9 (1) and 65.5 (1)° with the phenyl and 4-tolyl rings, respectively. In the crystal, stabilizing C-H⋯O, C-H⋯π and π-π inter-actions are evident. The calculated Hirshfeld surfaces highlight the prominent role of C-H⋯O inter-actions (8.6%), along with H⋯H (51.7%) and C⋯H/H⋯C (29.2%) surface contacts.