This monograph aims to describe the research performed to identify sustainable catalysts for the recycling of CO2 emissions and H2 generation . Chapter one consists of a general overview of both electrocatalytic and photocatalytic routes towards CO2 reduction and hydrogen evolution, the basis of the research presented in this thesis. Additionally, chapter one introduced is the background and theory of the various techniques that were used throughout the research; with a focus on the principles of photochemistry and electrochemistry. Chapter two commences with a literature review of the use of macrocyclic systems for the reduction of CO2 and hydrogen production; through both photochemical and electrochemical pathways. The syntheses of the porphyrin and metalloporphyrin catalysts used are discussed; and the subsequent investigation of these porphyrins for their ability to function as either photo- or electrocatalysts for both CO2 reduction and hydrogen evolution is described. The catalysts were characterised using 1H NMR, 13C NMR, Mass spectroscopy, UV-vis spectroscopy, emission spectroscopy and IR spectroscopy where applicable. Chapter three contains a literature review of the application of BODIPY systems focussing on the reduction of CO2 and hydrogen production. The syntheses of several boron dipyrromethene (BODIPY) systems are reported. Additionally, they were characterised with the usual range of spectroscopic techniques. The aforementioned systems were investigated for their ability to function as a photosensitiser for both hydrogen production and CO2 reduction.