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-2H-pyrido[1,6-a:2,3-d']di-pyrimidine-6-carbo-nitrile.

In the title compound, C21H15N5OS2, 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.

Crystal structure and Hirshfeld surface analysis of 5-oxo-7-phenyl-2-(phenyl-amino)-1H-[1,2,4]triazolo[1,5-a]pyridine-6,8-dicarbo-nitrile dimethyl sulfoxide monosolvate.

In the title compound, C20H12N6O·C2H6OS, the [1,2,4]triazolo[1,5-a]pyridine ring system is almost planar and makes dihedral angles of 16.33 (7) and 46.80 (7)°, respectively, with the phenyl-amino and phenyl rings. In the crystal, mol-ecules are linked by inter-molecular N-H⋯O and C-H⋯O hydrogen bonds into chains along the b-axis direction through the dimethyl sulfoxide solvent mol-ecule, forming C(10)R 2 1(6) motifs. These chains are connected via S-O⋯π inter-actions, π-π stacking inter-actions between the pyridine rings [centroid-to-centroid distance = 3.6662 (9) Å] and van der Waals inter-actions. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H⋯H (28.1%), C⋯H/H⋯C (27.2%), N⋯H/H⋯N (19.4%) and O⋯H/H⋯O (9.8%) inter-actions.