The replacement of fossil resources by sustainable and green synthetic fuels and chemicals is inevitable to reduce the emission of CO2 significantly and thus to combat climate change. Direct photocatalysis is an appealing one-step method to generate hydrogen as storable fuel from water using sunlight as energy source, especially because no complicated setups are required, thus such a process could be easily decentralized and also carried out in industrially less-developed areas. The key compound for photocatalysis is a solid semiconductor, which after light irradiation generates charge carriers, to drive the required reduction/oxidation reactions. The Thomas group develops porous organic photocatalysts, such as COFs and CMPs which can be prepared at ambient conditions, allowing to tailor their structure and optoelectronic properties for the desired reaction. Beside photocatalytic water splitting we are also working on photocatalytic CO2 reduction, H2O2 production and metallaphotocatalysis.