Redox reactions are often, if not most often, coupled to proton transfer events. Such proton-coupled electron transfer (PCET) reactions are important in chemical energy conversion reactions as the water oxidation reaction or in fuel cells, which are usually mediated by metal compounds. The underlying elementary steps are also commonly subject to quantum chemical benchmarking, from ionization to electron attachment, or even hydrogen atom transfer. The latter reference data are, however, far from the systems and the conditions commonly featured in catalysis, focusing on gas phase reactivity with light main-group elements. In the BENCh project, we will explore PCET reactions involving 3d metal/ligand reactivity in solution. The solution thermochemistry of the elementary steps of formally spin forbidden and spin allowed PCET reactions will be investigated in different, aprotic solvents as well as the solution BDFE of the HAT reaction.