Reaction of the nine-nuclear cluster Ni-9(HOOCCMe3)(4)(mu(4)-OH)(3)(mu(3)-OH)(3) (OOCCMe3)(12) (1) with pyridine results in the binuclear species Py4Ni2(OOCCMe3)(2)(mu-OCCMe3)(2)(mu-OH2) (2). Thermolysis of 2 at 100-140 degrees C in toluene or xylene leads to complex Py2Ni2(HOOCCMe3)(2)(OOCCMe3)(2)(mu-OOCCMe3)(2)(mu-OH2) (3). This complex can be converted back in 2 by the reaction of 3 with 2 equiv of pyridine. Thermolysis of solid 3 in vacuo at 170 degrees C gives the binuclear tetra-bridged trimethylacetate Py2Ni2(mu-OOCCMe3)(4) (4) which can be reverted ill 3 by reaction with 1 equiv of H2O and 2 equiv of HOOCCMe3. Compound 4 might be also prepared by the reaction of the complexs L2Ni2(mu-OOCCMe3)(4) (L = 2,3-lutidine (5), Et3N (6)) with pyridine at 40-80 degrees C in hexane or benzene solution. Complexes 5 and 6 are formed in an one-step reaction by interaction of complex 1 and ligand L. Complex Dipy(2)Ni(2)(OOCCMe3)(2)(mu-OOCCMe3)(2)(mu-OH2) (7), an isoelectronic analogue of complex 2, was prepared by reacting 1 with Dipy. Thermolysis of solid 7 at 170 degrees C in vacuo gives monomer DipyNi(OOCCMe3)(2) (8). Hetero-ligand complex DipyNi(NH2Ph)(OOCCMe3)(2) (9) was obtained upon the reaction of PhNH2 with complex 7 at 20 degrees C in benzene or MeCN. Reaction of 1 with alpha,alpha,alpha'-tripyridyl leads to the formation of the monomeric TerpyNi(OOCCMe3)(2) (10). Complexes 4-10 were characterized with X-ray data. Magnetic properties of the synthesized complexes are discussed.