The present Book describes research on synthesis and characterization of metal complexes for biological evaluations. Metal ions complexes can be introduced into a biological system either for therapeutic effect or as diagnostic aids. Here, focus on this book for design and synthesis of copper (II) and palladium (II) complexes, which exhibit, antibacterial activity (MIC) against Gram (-ve) and Gram (+ve) bacteria, Interaction between small molecules and DNA can often cause DNA damage in cancer cells and also investigate cytotoxicity studies.