2-[2-(4-Acetyl-phen-yl)hydrazinyl-idene]-1,3-diphenyl-propane-1,3-dione.

In the mol­ecular structure of the title compound, C21H15N3O4, the inter­planar angle between the benzoyl units is 89.7 (1)°. The corresponding angles between the phenyl­hydrazono and the benzoyl groups are 31.4 (3) and 60.8 (2)°, respectively. In the crystal, a strong resonance-assisted intra­molecular hydrogen bond (N—H⋯O) and a weak intra­molecular hydrogen bond (C—H⋯N) strongly affect the observed conformation of the mol­ecule. The crystal packing is determined by a strong inter­molecular hydrogen bond (N—H⋯O), giving rise to a helical chain along the a axis. In addition, two weak inter­molecular contacts (C—H⋯O) are observed.