A novel ZnII complex of the saccharinate ligand (sac) with tris-hydroxymethylaminomethane (tham) was synthesized and characterized by elemental analysis, FT-IR spectroscopy, simultaneous TG and DTA techniques, and X-ray diffraction. The complex, [Zn(sac)(tham)2](sac), crystallizes in monoclinic system with space group P21/c [a = 7.55954(3) Å, b = 13.0532(6) Å, c = 27.7777(10) Å, β = 100.539(3)°, Z = 4]. The ZnII ion has a distorted octahedral coordination. The tham ligand has chemically different functions in the structure, acting as both bidentate and tridentate ligands. There are also sac moieties to act as N-bonded ligand and as a counter anion. The molecular packing of the complex is provided by moderate hydrogen bonds as well as π⋯π interactions between the sac moieties. The IR spectra and the thermal decomposition of the complex are also discussed. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.