Crystal structure of the 1:1 adduct of ()-5-(2,3-di-hydro-benzo[]thia-zol-2-yl-idene)-2,6-dioxo-4-phenyl-1,2,5,6-tetra-hydro-pyridine-3-carbo-nitrile and its piperidinium salt, piperidinium ()-5-(benzo[]thia-zol-2-yl)-3-cyano-6-oxo-4-phenyl-1,6-di-hydro-pyridin-2-olate.

In the structure of the title compound, CHN·CHNOS·CHNOS, the central pyridinic rings are approximately coplanar to the benzo-thia-zole moieties. The phenyl groups are appreciably angled to the central rings [inter-planar angles of 57.30 (3)° for the anion and 79.01 (4)° for the neutral mol-ecule]. Bond lengths and angles correspond to considerable delocalization of the π bonding, especially for the anion; all four C=O bond lengths are similar [1.2365 (13)-1.2591 (13) Å]. The two main residues display different configurations about the formally double C-C bonds between the benzo-thia-zole and pyridinic ring systems; the neutral mol-ecule is , facilitating an intra-molecular N-H⋯O hydrogen bond, but the anion is , allowing a short intra-molecular S⋯O contact of 2.5794 (10) Å. Within the asymmetric unit, the piperidinium cation is hydrogen bonded to an oxygen atom of the anion; the anion and the neutral mol-ecule are connected by two N-H⋯O hydrogen bonds, forming a ring of graph-set (8). Asymmetric units are linked to form inversion-symmetric dimers by an H⋯O hydrogen bond. These are further linked by a C-H⋯O hydrogen bond to form a broad ribbon of residues parallel to the axis.