Currently there is a global energy crisis due to a dependence on non-renewable fossil fuels. Solar fuel is in generous surplus, and can be harnessed throughout a variety of different chemical and biological processes. In this body of work, there is a focus on two different types of synthetic dyes; the porphyrin and BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-sindacene). Both dyes exhibit excellent photophysical characteristics; absorbing strongly within the visible region, high fluorescent quantum yields and molar extinction coefficients. Additionally, these dyes exhibit high degrees of synthetic flexibility permitting tunability of photophysical characteristics through functionalisation. This work describes dyes that may appear similar, but due to their functionalisation exhibit vastly different photophysical characteristics. Critical characteristics of porphyrin sensitised photocatalytic hydrogen generating systems are reviewed in detail in Chapter 2. A series of zinc-porphyrins substituted with thienyl-type ligands is described in Chapter 3, with a focus on photophysical analysis. In Chapter 4, a porphyrin-rhenium dyad was synthesised towards photocatalytic carbon dioxide reduction. Moving towards the BODIPY, a photophysical and time-resolved study of a phenylacetylene functionalised BODIPY was executed in Chapter 5. This study probed the excited state dynamics and established notable structural changes in the BODIPY skeleton post excitation. In Chapter 6, a series of diiodinated BODIPY dyes towards photocatalytic hydrogen generation were characterised. Despite each study utilising a different technique for application, the photophysical characteristics of each dye were investigated. For all studies, the use of time-resolved techniques were imperative to probing the excited state dynamics of the different systems. The work described here provide insight into the photophysical and excited state dynamics of differently functionalised porphyrin and BODIPY dyes. Extension of backbone conjugation results in broader absorption of visible light, resulting in improved solar absorption. Moreover, investigation into the excited state dynamics bey