The photocatalytic proton reduction allows to produce hydrogen sustainably by harvesting sunlight with catalytic devices. Within this doctoral thesis, the application of iron based photosensitizers in this reaction was investigated. In order to generate a deepened understanding of the photophysics, homo- and heteroleptic complexes were synthesized with systematic variation of the number of strong -donors and -acceptors, respectively. Thorough physicochemical investigations by means of CV, UV-Vis-, fluorescence- and X-ray spectroscopy gave insights into structural and geometric ground state properties. Based on this, the photodynamics was investigated by optical TA spectroscopy, which was supported by spectro-electrochemical measurements.As a result, two basic strategies for the elongation of the 3MLCT lifetime being relevant for photocatalysis and electron transfer, respectively, were verified systematically. In summary, properties being essential for photosensitizers (excited state lifetime, redox- and absorption properties) could be understood and tuned specifically. Within this thesis the way to intramolecular electron transfer was paved, too. Thorough physico- and photochemical investigation of bimetallic systems lay the foundation for a direct photo induced charge transfer having great potential in photocatalytic reactions.