The trans-bis(saccharinato)nickel(II) complexes with 2-aminomethylpyridine (ampy) and 2-aminoethylpyridine (aepy) have been prepared and characterized by elemental analyses, i.r., u.v.-vis., magnetic measurements and single crystal X-ray diffraction. Both structures consist of discrete molecules of the title complexes, in which the nickel( II) ion lies on an inversion centre and is octahedrally coordinated by two bidentate (N, N') ampy or aepy ligands and two anionic sac ligands, occupying trans positions. The most interesting feature of the complexes is the coordination of sac. In [Ni(sac)(2)(ampy)(2)], sac is N-bonded, whereas it is O-coordinated in [Ni(sac)(2)(aepy)(2)]. The i.r. spectra and thermal behaviour of both complexes are discussed in detail.