A nickel(II) complex with an unsymmetrical tetradentate chelating ligand derived from pyridine-2,6-dicarbaldehyde and 2-aminothiophenol

[(2-{[6-(1,3-Benzo­thia­zol-2-yl)pyridin-2-yl]carbonyl­aza­nid­yl}phen­yl)sulf­anido]nickel(II), [Ni(C$_{19}$H$_{11}$N$_3$OS$_2$)], crystallizes in the centrosymmetric monoclinic space group $P2_1/n$ with one mol­ecule in the asymmetric unit. The expected ligand, a bis-Schiff base derived from pyridine-2,6-dicarbaldehyde and 2-amino­thio­phenol, had modified in situ in a both unexpected and unsymmetrical fashion. One arm had cyclized to form a benzo[$d$]thia­zol-2-yl functionality, while the imine linkage of the second arm had oxidized to an amide group. The geometry about the central Ni$^{II}$ atom is distorted square-planar N$_3$S. The mol­ecules form supra­molecular face-to-face dimers via rather strong π–π stacking inter­actions, with these dimers then linked into chains via pairwise C—H$\cdot\cdot\cdot$O inter­actions.