4-{2-[2-(4-Chloro-benzyl-idene)hydrazinyl-idene]-3,6-dihydro-2H-1,3,4-thia-diazin-5-yl}-3-phenyl-sydnone.

The title compound, C(18)H(13)ClN(6)O(2)S, exists in trans and cis configurations with respect to the acyclic C=N bonds [C=N = 1.2837 (15) and 1.3000 (14) Å, respectively]. The 3,6-dihydro-2H-1,3,4-thia-diazine ring adopts a half-boat conformation. The sydnone ring is approximately planar [maximum deviation = 0.002 (1) Å] and forms dihedral angles of 50.45 (7) and 61.21 (6)° with the aromatic rings. In the crystal, inter-molecular N-H⋯N, C-H⋯Cl and C-H⋯S hydrogen bonds link the mol-ecules into layers parallel to ab plane. The crystal packing is stabilized by C-H⋯π inter-actions and further consolidated by π-π inter-actions involving the phenyl rings [centroid-centroid distance = 3.6306 (7) Å].