The magnificent roles of cisplatin as a cancer therapeutic agent enthused the progress of metal-based therapeutics or diagnostic agents in the modern era. In such inorganic pharmaceuticals or probes, coordination chemistry in the biological environment or at the target site reclines at the heart of their modes of action. Therefore, molecular designing of new metal-based drugs or imaging probes by tuning the coordination environments, provides the opening in the alteration and improvement of such agents, thus raising metal-based compounds as promising pharmacological candidates. Presently many metallodrugs are frequently administered to patients for therapeutic and diagnostic benefits. In this regard, for designing more efficient metallodrugs, choosing an appropriate metal ion and bioactive ligand plays a significant role. Also, tuning the coordination environment of the metal complexes improves the catalytic efficiency as compared to the metal salts. Therefore, in my dissertation, knowing the importance, ease, and cost-friendly availability, two 1st row transition metals i.e., vanadium and nickel, and one p-block metal i.e., tin have been chosen for synthesizing their respective complexes taking different bioactive dibasic ligands and further studies their biological and catalytic relevance. From the overall studies, few of the test compounds were found to be a good binder with DNA and proteins. Based on the ligand environments, appropriate metals were selected and evaluated for cellular uptake capacity, lipophilicity, and cytotoxicity. Many of the synthesized complexes were defined as better cytotoxic agents for killing cancer cells or as bioimaging probes for tracking cellular organelles in real-time. The obtained results herein showed parallel, or in some cases even better in vitro cytotoxicity in contrast to many clinically testified chemotherapeutic drugs. Some of the complexes might be used as an equal or better organelle tracking agent compared to commercially available organelle trackers. Apart from this, some synthesized Ni complexes have been studied as catalysts for the synthesis of heterocyclic derivatives through multicomponent reactions.