The　two　trinuclear　nickel(II)　complexes,　Ni-3(C13H15N2O3)(2)(C5H5N)(4)　(1)　and　Ni-3(C13H15N2O3)(2)(C5H5N)(2)(C3H7NO)(2)　(2),　were　prepared　by　the　reaction　of　Ni(OAc)(2)center　dot　4H(2)O　with　N-hexanoylsahcylhydrazide.　The　crystal　structures　of　complexes　were　determined　by　X-ray　diffraction　analysis.　Complex　1　takes　triclinic　symmetry　with　space　group　P-1　and　cell　dimensions　of　a=0.92377(2)　nm,　b=1.08786(6)　nm,　c=1.29391(3)　nm,　alpha=76.395(4)degrees,　beta=78.418(3)degrees,　gamma=67.378(4)degrees,　V=1.15772(7)　nm(3),　Z=　1,　mu=12.63　cm(-1).　Complex　2　belongs　to　triclinic　system　and　P2(1)　space　group　and　the　crystallographic　data:　a=1.4889(2)　nm,　b=1.0389(1)　nm,　c=1.4994(2)　nm,　beta=96.174(4)degrees,　V=2.3058(5)　nm(3),　Z=2,　mu=12.70　cm(-1).　The　structures　of　the　two　molecules　are　similar.　The　three　nickel　atoms　in　each　molecule　of　the　two　title　complexes　arrange　in　a　strictly　linear　structure.　The　central　nickel　atom　of　the　molecule　adopts　octahedral　configuration,　while　the　two　nickel　atoms　on　the　two　sides　adopt　square-planar　configuration　in　each　molecule.　But　the　central　nickel　atoms　of　the　two　complexes　have　different　axial　ligands,　which　cause　a　slight　difference　in　the　bond　distances　of　the　octahedron.　The　antibacterial　activity　of　compound　1　against　seven　common　bacteria　was　investigated.