4-{(Z)-2-[(E)-Benzyl­idenehydrazinyl­idene]-3,6-dihydro-2H-1,3,4-thia­diazin-5-yl}-3-phenyl-1,2,3-oxadiazol-3-ium-5-olate

The title compound, C(18)H(14)N(6)O(2)S, exists in trans and cis configurations with respect to the two acyclic C=N bonds [bond lengths = 1.2835 (9) and 1.3049 (9) Å]. The 3,6-dihydro-2H-1,3,4-thia­diazine ring adopts a half-boat conformation. The oxadiazol-3-ium ring makes dihedral angles of 53.70 (4) and 60.26 (4)° with the two phenyl rings. In the crystal, mol­ecules are linked via pairs of inter­molecular N—H⋯N hydrogen bonds, generating R (2) (2)(8) ring motifs, and are further linked via inter­molecular C—H⋯O and C—H⋯S hydrogen bonds into a three-dimensional network. The short inter­molecular distance between the oxadiazol-3-ium rings [3.4154 (4) Å] indicates the existence of a π–π inter­action.