Abstract: | In the crystal structure of the title compound systematic name: diaquabis(6‐methyl‐2,2‐dioxo‐1,2,3‐oxathiazin‐4‐olato‐κO4)bis(3‐methylpyridine‐κN)nickel(II)], Ni(C4H4NO4S)2(C6H7N)2(H2O)2], the NiII centre resides on a centre of symmetry and has a distorted octahedral geometry. The basal plane is formed by two carbonyl O atoms of two monodentate trans‐oriented acesulfamate ligands and two trans aqua ligands. The axial positions in the octahedron are occupied by two N atoms of two trans pyridine ligands. Molecules are stacked in columns running along the a axis. There are π–π stacking interactions between the molecules in each column, with a distance of 3.623 (2) Å between the centroids of the pyridine rings. There are also O—H⋯O interactions between the columns. |