Organometallic and coordination complexes have shown potential and found applications as therapeutics in treating a variety of diseases, from cancer to microbial infections. Metals offer distinct therapeutic opportunities compared to traditional organic drugs due to the diversity of accessible geometries, varied modes of interaction with biomolecules, and range mechanisms of action. This thesis focuses on the exploration and fine tuning of metal complexes as potential therapeutics, aiming at elucidating structure-activity relationships in metal drugs and study under investigated chemical space. After a brief overview of medicinal inorganic chemistry and metal drugs in Chapter 1, Chapter 2 introduces our work on cationic ruthenium(II) arene phosphine complexes. The cytotoxicity of ruthenium arene complexes with different lipophilicities was evaluated, identifying [Ru(toluene)(PPh3)2Cl]+ as a promising candidate for breast cancer treatment. The complex demonstrated considerable cytotoxicity and selectivity against breast cancer cell lines. Additionally, the influence of counterions on cytotoxicity and selectivity was investigated, revealing an intricate balance between ion-pairing and lipophilicity as key factors in modulating the biological behaviour of these compounds. Chapter 3 explores the synthesis of non-classical azolium-based N,Y-heterocyclic carbene (Y = S, O, Se) metal complexes. Platinum, gold, and ruthenium compounds were selected based on their reported biological activity, and their (benz)oxazole, (benzo)thiazole, and benzoselenazole analogues were synthesized. The effect of the substitution of nitrogen for chalcogens was investigated, with the study focusing on the mechanism of action of the complexes in cellulo. The obtained results emphasize the importance of ligand modification in directions of previously uncharted chemical space. Chapter 4 investigates a series of ruthenium(II) arene triphenylpnictogen complexes (P, As, Sb) for their antiproliferative activity against ovarian cancer cells. It also explores the modulation of activity based on the different pnictogen atoms. Additionally, novel Ru-Bi heterobimetallic complexes with unique architectures were synthesized and characterized, contributing further to the exploration of innovative metal-based therapeutics. Chapter 5 covers the development of thermoresponsive anticancer drugs: platinum(IV) carboplatin prodrugs and novel perfluorinated melphalan derivatives. The compounds were designed to act in combination with heat (with hyperthermia or focal therapy) to enhance their activity and selectivity. The compounds showcase the potential of heat-activated therapies to improve patient outcomes. Overall, this thesis provides a perspective on the critical role of chemical exploration, modification, and fine-tuning in advancing the development of new metal-based drugs.