Climate change is one of the biggest health threats faced by humanity with dire effects such as warmer temperatures and increased drought which in turn effects food sources such as crops, livestock and fisheries. One of the main causes of climate change is the use of non-renewable energy sources, fossil fuels which release carbon dioxide into the atmosphere when burnt causing heat to be trapped. A move away from fossil fuels is needed so new efficient and cost-effective photocatalytic systems must be developed to produce hydrogen energy in a clean manner using renewable resources such as sunlight and water. 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPYs) will be investigated for these purposes. BODIPY compounds have advantageous properties such as good solubility and high molar extinction coefficients. Polymerisation of BODIPY chromophores causes broadening and red shifts further into the visible region in the absorbance spectra compared to the analogous parent BODIPY, which may help to encourage H2 generation. While decreasing the amount of CO2 being released into the atmosphere can be helped through synthesis of systems that can produce hydrogen fuel in a clean, renewable way without the use of fossil fuels, the CO2 that is already in the atmosphere is still a problem. It is important that systems that could be used for CO2 reduction to CO were also studied. Three novel rhenium N-heterocyclic carbene complexes [Re]-NHC ([Re] = fac-Re(CO)3Br) were synthesized and studied as part of a system to reduce CO2 under UV irradiation, all three being efficient photocatalysts for reduction of CO2. An investigation into TRIR data of these compounds were also conducted. Photocatalytic systems reported in literature are often very different and their parameters so varied it is difficult to compare each systems directly. Therefore, an investigation into how each component effects the efficiency of hydrogen evolution systems containing porphyrins was carried out.