Light induced release of nitric oxide and carbon monoxide from metal complexes The present thesis focuses on the light responsive nitric oxide releasing molecules (NORMs) and carbon monoxide releasing molecules (CORMs) based on transition metal ruthenium (Ru) and manganese (Mn) complexes. A general introduction and brief development of NORMs and CORMs are given in the first chapter. Chapter 2 describes series of photolabile {RuNO}6 nitrosyls containing carboxamido N and pyridine donors which fluorine substitution at different positions within the molecules thereof. In this section the synthesis and characterization of metal nitrosyls are introduced as well as the influence of fluoro substitution on NO releasing studies are also investigated. In addition the photo behaviors and mechanism analysis of the fluorinated ruthenium carbonyl complexes with same ligands as {RuNO}6 nitrosyls are represented in chapter 3. Next the Chapter 4–6 demonstrate water soluble photo CORMs based on manganese(I) tricarbonyls center which conjugated to a fluorobenzene group dabsyl chromophoric ligand and nitrobenzodiazole fluorophore group respectively. A fluorinated manganese based photo CORM in chapter 4 combines with 19F spectroscopy aiming to provide a new strategy for tracking the photolysis of donor molecules through the NMR spectral change. Furthermore the photo CORMs presented in chapter 5 and 6 release CO under irradiation with visible light simultaneously achieving the colorimetric and or fluorometric response.