A nickel(II) complex of saccharinate (sac) with N-(2-aminoethyl) piperazine (aeppz), trans-[Ni(sac)(2)(aeppz)(2)], has been prepared and characterized by elemental analyses, IR, UV-vis, magnetic measurements and single crystal X-ray diffraction. The compound crystallizes in space group P1 (No. 2). The nickel(II) ion sits on an inversion centre and is octahedrally coordinated by two neutral aeppz and two anionic sac ligands. The aeppz ligand is bidentate (N, N') chelating, while sac is O-coordinated through the carbonyl O atom. The IR spectrum of [Ni(sac)(2)(aeppz)(2)] displays typical absorption bands of bidentate aeppz and O-bonded sac ligands. Under atmospheric conditions, [ Ni( sac) 2( aeppz) 2] is thermally stable up to 220 degrees C, but at higher temperatures, loses two aeppz ligands between 220 and 317 degrees C and two sac ligands in the temperature range 320-528 degrees C, giving NiO as end product.