Porous organic polymers (POPs) have long been considered as prime candidates for carbon dioxide (CO₂) capture, separation, and conversion. Especially their permanent porosity, structural tunability, stability and relatively low cost are key factors in such considerations. Whereas heteratom-rich microporous networks as well as their amine impregnation/functionalization have been actively exploited to boost the CO₂ affinity of POPs, recently, the focus has shifted to engineering the pore environment, resulting in a new generation of highly microporous POPs rich in heteroatoms and featuring abundant catalytic sites for the capture and conversion of CO₂ into value-added products. In this review, we aim to provide key insights into structure–property relationships governing the separation, capture and conversion of CO₂ using POPs and highlight recent advances in the field.