In part I, two new trans Pd (II) complexes , trans-Pd(PhCH2NH2)2Cl2 (1), trans-[Pd(PhCH2NH2)2(Let)2](NO3)2 (2), (Let= Letrozole drug; 4,4'-((1H-1,2,4-triazol-1-yl)methylene)dibenzonitrile), have been synthesized and characterized by elemental analysis, FT-IR and NMR spectroscopy. Single crystal X-ray diffractometry has been used to determine the crystal structure of 1. UV-Vis spectroscopy, emission titration, circular dichroism and helix melting methods have been used to study the binding interaction of Pd (II) complexes with Calf Thymus deoxyribonucleic acid (CT-DNA). The analysis results show that (1) can interact with DNA via groove binding and (2) binds to DNA through partial intercalation mode. It was found that the binding constants (Kb) of the complexes toward BSA were (1.4×104M-1) and (1.68×104 M-1) for (1) and (2), respectively. Competitive binding using Warfarin, Ibuprofen and Digoxin site markers with definite binding sites demonstrated that the binding site for (1) was mainly located within site II of BSA. The result of the competitive titration of (2) was different. In the presence of Warfarin, the Kb value decreased, showing a competition between (2) and Warfarin. In addition, molecular docking studies have been conducted to determine the binding site of the DNA and BSA with complexes. Finally, In vitro cytotoxicity of (1), (2) and cisplatin were carried out against leukemia cancer (Raji), lung cancer (A549) and breast cancer (MCF7) cell lines. According to the IC50 values, the cytotoxicity of (2) was more than (1). In part II, new palladacyclic dimer [Pd2((C,N)L)2(µ-Sac)2] (3), in which L: C14H11NBr and sac: saccharinate ligand, has been synthesized and characterized by elemental analysis, FT-IR and NMR spectroscopy. X-ray crystallography has been used to determine the single crystal structure of this Pd(II) complex. In this dimer, two palladium(II) center are bridged by saccharinate anion, which is coordinated to the cyclopalladated units as a bidentate (N- and carbonyl O- atoms) ligand. According to DNA binding studies (UV-Vis spectroscopy, emission titration and viscosity measurement), the Pd(II) complex interacts with Calf-thymus DNA (CT-DNA) through groove binding mode. Furthermore, UV-Vis and fluorescence emission spectroscopy have been used to monitor the binding of the complex to bovine serum albumin (BSA). The complex is mainly located in site I of the protein, based on the competitive experiments using Warfarin, Ibuprofen and Digoxin as site markers. The results of molecular docking confirmed the experimental data. Finally, the In vitro cytotoxicity of sodium saccharin, ligand LH (C14H12NBr), complex (3) and cisplatin against cervical cancer (HeLa), lung cancer (A549) and breast cancer (MCF-7) cell lines has been studied. Complexation process has significantly improved the anticancer activity, as IC50 values show. Furthermore, (3) has been tested against NIH normal fibroblast cells. Therefore based on the SI definition, (3) can be imputed as the selective compound against cancer cells. In part III, a new Pd(II) complex, [Pd(C6H5N2O)2] (4), with an oxime ligand that is pyridine-2-carbaldehyde oxime was prepared and characterized by elemental analysis, FT-IR, NMR and mass spectroscopy. X-ray crystallography has been used to determine the single crystal structure of this Pd(II) complex. The DNA binding studies (UV-Vis spectroscopy, emission titration and viscosity measurement) show that (4) interacts with calf-thymus DNA (CT-DNA) via groove binding interaction. The DNA cleavage activity of the oxime ligand and complex (4) was measured, indicating that complex (4) effectively promoted the cleavage of plasmid DNA in the presence and/or absence of activating agent (peroxide oxygen) at physiological conditions. The mechanism of plasmid DNA cleavage was also studied by adding standard radical scavengers. The microenvironment and the secondary structure of BSA were also changed in the presence of complex (4). The complex is mainly located in site I of the protein, based on the competitive experiments using Warfarin, Ibuprofen and Digoxin as site markers.The complex was remarkable in exhibiting cleavage of the BSA at physiological pH and temperature. The binding of the complex (4) to DNA and BSA was modeled by molecular docking. Finally, the anticancer effects of the free oxime ligand and complex were tested in vitro against tumor cell lines, including the mouse colon carcinoma (C26) and mouse melanoma cells (B16-F0). Complexation process has significantly improved the anticancer activity. Both compounds showed the IC50 values less than those of cisplatin against cancer cell lines. Furthermore, oxime ligand and complex (4) have been tested against NIH normal fibroblast cells. Therefore based on the SI definition, they can be imputed as the selective compound against cancer cells.