Crystal structure and Hirshfeld surface analysis of ethyl 2-[5-(3-chloro-benz-yl)-6-oxo-3-phenyl-1,6-di-hydro-pyridazin-1-yl]acetate.

The title pyridazinone derivative, C(21)H(19)ClN(2)O(3), is not planar. The unsubstituted phenyl ring and the pyridazine ring are inclined to each other, making a dihedral angle of 17.41†(13)° whereas the Cl-substituted phenyl ring is nearly orthogonal to the pyridazine ring [88.19†(13)°]. In the crystal, C-H⋯O hydrogen bonds generate dimers with R (2) (2)(10) and R (2) (2)(24) ring motifs which are linked by C-H⋯O inter-actions, forming chains extending parallel to the c-axis direction. The inter-molecular inter-actions were investigated using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing that the most significant contributions to the crystal packing are from H⋯H (44.5%), C⋯H/H⋯C (18.5%), H⋯O/H⋯O (15.6%), Cl⋯H/H⋯Cl (10.6%) and C⋯C (2.8%) contacts.