(E)-5-(4-Chloro-benzyl-idene)-1-phenyl-4,5,6,7-tetra-hydro-1H-indazol-4-one: crystal structure and Hirshfeld surface analysis.

In the title compound, C20H15ClN2O, the non-aromatic six-membered ring adopts a distorted envelope conformation with methyl-ene-C atom nearest to the five-membered ring being the flap atom. The dihedral angle between the phenyl and chloro-benzene rings is 74.5 (1)°. The heterocyclic ring forms dihedral angles of 37.9 (1) and 64.3 (1)° with the phenyl and chloro-benzene rings, respectively. In the crystal, weak C-H⋯O inter-actions feature predominantly within the three-dimensional architecture. The inter-molecular inter-actions are further analysed with the calculation of the Hirshfeld surfaces highlighting the prominent role of C-H⋯O inter-actions, along with H⋯H (36.8%) and C⋯H/H⋯C (26.5%) contacts.