Heterogenous catalysts with confined nanoporous catalytic sites are shown to have high activity and size selectivity. A solution-processable nanoporous organic polymer (1-BPy-Pd) catalyst displays high catalytic performance (TON > 200K) in the heterogeneous Suzuki–Miyaura coupling (SMC) reaction and can be used for the preparation of the intermediates in the synthesis of pharmaceutical agents. In comparison to the homogeneous catalyst analogue (2,2′-BPy)PdCl2, the heterogenous system offers size-dependent catalytic activity when bulkier substrates are used. Furthermore, the catalyst can be used to create catalytic impellers that simplify its use and recovery. We found that this system also works for applications in heterogenous Heck and nitroarenes reduction reactions. The metal-binding nanoporous polymer reported here represents a versatile platform for size-selective heterogeneous and recyclable catalysts.