The ONO donor ligands form a significant class of compounds in medicinal and pharmaceutical chemistry and are known to have biological applications due to their antibacterial, antifungal, and antitumor activity. The design and synthesis of various ONO donor ligands significantly contribute to developing the coordination chemistry of transition metal complexes. By systematically exploring the structural versatility and coordination preferences of these ligands, one can examine their crucial role in modulating the properties and reactivities of metal complexes. Among transition metals, the chemistry of nickel and copper complexes received significant attention among the research community because of their biological relevance. However, the biological applications of nickel(II) and copper(II) species are yet to be explored more. The incorporation of transition metals into these ONO ligands leads to the enhancement of their biological activities and an increase in the cytotoxicity of resulting complexes. The plan for this doctoral research is precisely aimed to design few ONO donor ligand systems and the study of their coordination behavior towards transition metal complexes (for example Ni, Cu, etc.) and study their biological activity. All the ligands and metal complexes will be characterized by various analytical methods, UV-vis, IR, NMR, CV, HRMS, and SC-XRD techniques. Efforts will also be made to investigate and understand the structure-activity relationships of metal complexes in biological systems.