The re-integration of C1-sources like CO2 and CH4 into the chemical value chains is one of the major challenges of our time. Both molecules, although abundant and cheap, show a high thermodynamic stability, such that the means to overcome the high activation energy is key. Besides the well investigated thermal conversion, novel routes must be developed. The proposed research will therefore focus on the development and optimization of hybrid photosystems for CO2 reduction. We will investigate the influence of new (nano-structured) pulsed light sources on the photostability and photocatalytic activity of the CO2 reduction (Stutzmann/Rieger). New light sources, which can deliver a pulsed photon flux on the low nano-second scale will be developed (Stutzmann). Novel, (multi)nuclear complexes, including those based on earth-abundant elements, will be applied (Hess/Rieger). For the development of viable, high efficiency photocatalysts, the molecular catalysts must be combined with surfaces, which serve as active supports, delivering a constant photon flux and stabilizing molecular complexes against deactivation processes. Therefore, a final part of this proposal will focus on chemical anchoring of molecular complexes on the surface of GaN-holo nano-fibers, as well as on photoluminescent silicon nanocrystals and on flat silicon-based semiconductor surfaces (Rieger/Stutzmann).