Crystal structure and Hirshfeld surface analysis of 4-oxo-3-phenyl-2-sulfanyl-idene-5-(thio-phen-2-yl)-3,4,7,8,9,10-hexa-hydro-2 H -pyrido[1,6- a :2,3- d ']di-pyrimidine-6-carbo-nitrile.

In the title compound, C 21 H 15 N 5 OS 2 , mol-ecular pairs are linked by N-H⋯N hydrogen bonds along the c- axis direction and C-H⋯S and C-H⋯O hydrogen bonds along the b- axis direction, with R 2 2 (12) and R 2 2 (16) motifs, respectively, thus forming layers parallel to the (10) plane. In addition, C=S⋯π and C≡N⋯π inter-actions between the layers ensure crystal cohesion. The Hirshfeld surface analysis indicates that the major contributions to the crystal packing are H⋯H (43.0%), C⋯H/H⋯C (16.9%), N⋯H/H⋯N (11.3%) and S⋯H/H⋯S (10.9%) inter-actions.