This thesis focuses on the development of functional Porous Organic Frameworks (POFs) for various catalytic applications. POF supported molecular catalysts allow to combine the advantages of both homogeneous and heterogeneous catalysts, offering excellent prospects in the quest to heterogenize homogeneous catalysts. The framework tunability of POFs can be used to obtain an optimal catalytic performance, while the fully heterogeneous character of the POFs allow easy handling and recycling. In some cases, they may even directly participate in the catalytic cycle by activating substrates.Advisors/Committee Members: Kapteijn, F., Makkee, M., Gascon Sabate, J..