In this thesis, the use of high performance liquid chromatography (HPLC) for the analysis, assessment and characterisation of photocatalytic behaviour. The Ru(II) compounds are coordinated at peripheral ligands to create at Ru(II) centre, while bridging ligands are used to connect the ruthenium centre to the Pt catalytic centres in order to create intramolecular systems. The properties of these platinum-containing compounds were compared with the mononuclear ruthenium precursor, without a platinum centre, in terms of photostability and catalytic activity. These intramolecular platinum containing compounds are aimed at create photocatalysts in combination with terminal halogen atoms (iodide or chloride). UV-vis absorption and 1H-NMR analysis were carried out to provide further detailed qualitative and structural information as a result of the photocatalytic experiments terminal, halogen atoms (iodide or chloride) and range of techniques where discussed, to provide further detailed and structural information. UV-vis absorption and 1H-NMR analysis were carried out to provide further detailed information about the possible chemical changes taking place after irradiation as a result of the photocatalytic experiments. In Chapter 1, a number of relevant topics are discussed and the studies presented in this thesis in order to explain our research targets and experimental techniques. In Chapter 2, the introduction to HPLC, analytical HPLC, HPLC setup, mobile phases and UV-Vis Spectroscopy used and 1H NMR spectroscopy are discussed and sample preparation for photoanalysis with TEA and without TEA were explained. In Chapter 3 stability towards visible light by the complexes [(bpy)2Ru(2,3dpp)]2+ (A-I), [(bpy)2Ru(2,3dpp)PtCl2] 2+ (A-II), and [(bpy)2Ru(2,3dpp)PtI2] 2+ (A-III) were carried out. Without TEA all three compounds the compounds are mostly photostable, but in the presence of TEA decomposition of the compounds is observed. In Chapter 4, for the compounds [(phen)2Ru(2,3dpp)]2+ (B-I), [(phen)2Ru(2,3dpp)PtCl2] 2+ (B-II), and [(phen)2Ru(2,3dpp)PtI2] 2+ (B-III), compounds B-I and B-II are photostable and B-III is partially photostable. In the presence of TEA, changes in the coordination of the bridging ligands are observed. In Chapter 5 compounds [(dceb)2Ru(2,3dpp)]2+ (C-I), [(dceb)2Ru(2,3dpp)PtCl2] 2+ (C-II), and [(dceb)2Ru(2,3dpp)PtI2] 2+ (C-III) are discussed. In the presence of irradiation, compounds C-I and C-III are photoreactive while that compound C-II is photostable. The stability of irradiation in the presence of TEA compounds C-I, C-II and CIII are degrading fast. In Chapter 6 a general overview of the work carried out is discussed.