In the first section of this thesis, di-nuclear cyclopalladated acetate-bridge complexes ( 1-3 ) derived from secondary and tertiary benzylamines were prepared. Heating of bis amine-acetate complex 4 in benzene also resulted dinuclear acetate-bridge dimer. Metathetical reaction of acetate-dimers and bis amin complex 4 with an excess of NaCl or NaBr afforded the corresponding complexes ( 5 - 9 ). Monodentate and bidentate ligands can split the halide bridges to give monomerc complexes ( 10 - 13 ). Reaction between halide-bridge dimers with 1,2 bis(diphenylphosphino)ethane (dppe) in the 1:1 molar ratio resulted in the dppe-bridged Pd(II) complexes ( 15 - 17 ). In vitro cytotoxicity of dppe-bridged di-nuclear and some mono-nuclear complexes and cisplatin were carried out against various human tumor cell lines. Also, the interactions of complexes towards DNA and protein BSA are investigated. In the other part of this section, halide bridge complexes reacted with diphenyleacetylene to give 18 , 19 through a double insertion of the alkyne into the Pd-C ? bond. Also, di-inserted product 19 reacts with Ag(CF 3 SO 3 ) and pyridine to give mononuclear cationic complex 20 . In the second section of this thesis, some new nickel(II) complexes, [Ni(SCS)X] having SCS pincer ligands with two thioamide units have been synthesized and fully characterized by NMR spectroscopy and X-ray crystallography. The crystal structures of all complexes hint at significant delocalization of bonding in the thioamide units. In addition, cyclic voltammetry measurements of the compound containing secondary thioamide indicate that the secondary thioamide moiety is easily deprotonated to produce its thionate anionic form. Throughout the thesis X-ray crystallography has been used to verify or identify most of the products ( 20 structures).