Abstract The quest for effective technologies to reduce SO 2 pollution is crucial due to its adverse effects on the environment and human health. Markedly, removing a ppm level of SO 2 from CO 2 ‐containing waste gas is a persistent challenge, and current technologies suffer from low SO 2 /CO 2 selectivity and energy‐intensive regeneration processes. Here using the molecular building blocks approach and theoretical calculation, we constructed two porous organic polymers (POPs) encompassing pocket‐like structures with exposed imidazole groups, promoting preferential interactions with SO 2 from CO 2 ‐containing streams. Markedly, the evaluated POPs offer outstanding SO 2 /CO 2 selectivity, high SO 2 capacity, and an easy regeneration process, making it one of the best materials for SO 2 capture. To gain better structural insights into the notable SO 2 selectivity of the POPs, we used dynamic nuclear polarization NMR spectroscopy (DNP) and molecular modelling to probe the interactions between SO 2 and POP adsorbents. The newly developed materials are poised to offer an energy‐efficient and environment‐friendly SO 2 separation process while we are obliged to use fossil fuels for our energy needs.