Mimicking the fundamental processes of the photosynthetic reaction center is a large field of research over the past decade. We present as biomimetic model systems for electron transfer the mono- and heteroleptic ruthenium complexes 2-9 containing differently substituted bipyridazine-glycol ligands. Depending on the number of glycol chains of the complexes 2-9, they are divided into three classes : A (2 branches, 2-4); B (3 branches, 5-6) and C (6 branches, 7-9). UV, fluorescence, single-photon counting, and laser flash photolysis were employed as techniques for photophysical characterization. Redox properties were determined using cyclic voltammetry. Detailed steady-state quenching studies of 2-9 with MV2+, OV2+, and MPVS have shown different supramolecular interactions between sensitizer and acceptor in the case of MV2+. These effects may be explained by pi-pi donor-acceptor attractions as well as hydrophobic interactions. Supporting molecular modeling studies have been done. The suitability as biomimetic model systems was shown by testing the ruthenium complexes 2-9 in artificial photosynthesis systems. Two typical reactions were selected : the sacrificial reduction of water and the reduction of CO2 to CH4. The use of 2-9 leads to satisfactory hydrogen production from the reduction of water. In the CH4/CO2 system, complexes 7-9 worked efficiently.