Crystal structure, Hirshfeld surface analysis and energy framework study of 6-formyl-7,8,9,11-tetra-hydro-5H-pyrido[2,1-b]quinazolin-11-one.

At 100 K, the title compound, C13H12N2O2, crystallizes in the ortho-rhom-bic space group Pna21 with two very similar mol-ecules in the asymmetric unit. An intra-molecular N-H⋯O hydrogen bond leads to an S(6) graph-set motif in each of the mol-ecules. Inter-molecular π-π stacking and C=O⋯π inter-actions involving the aldehyde O atoms link mol-ecules into stacks parallel to [100]. A Hirshfeld surface analysis indicates that the most important contributions to the crystal packing stem from H⋯H (49.4%) and H⋯O/O⋯H (21.5%) inter-actions. Energy framework calculations reveal a significant contribution of dispersion energy. The crystal studied was refined as a two-component inversion twin.