<p>With the occurrence of nuclear accidents and advancements in nuclear medicine, the release of radioactive iodine poses great threats to environment and human health. Thus, the development of robust adsorbents for efficient capture of radioactive iodine is crucial. Herein, we report the design and synthesis of two cross-linked macrocycle-based porous organic polymers (P1 and P2) with different functionalities for efficient and rapid capture of radioactive iodine. P1 achieves complete iodine adsorption within 5 min with an exceptional adsorption rate constant (<i>k</i>_obs) of 18.92 g g⁻¹ min⁻¹ (8.24 g g⁻¹ min⁻¹ for P2), representing the record-high iodine removal rate among state-of-the-art porous organic polymers. Importantly, P1 demonstrates superior iodine adsorption efficacy in dynamic flow-through experiments, and it achieves a remarkable efficiency of 96.4% for radioactive ¹³¹I removal, greatly minimizing the radiation contamination. Experimental and modelling techniques reveal that the superior iodine adsorption performance originates from the electric-rich functional groups, hydrophobic surface and porous structure of P1, thus exhibiting remarkable iodine capture capabilities through charge transfer, halogen bonding, and hydrophobic effects. Meanwhile, these adsorbents show excellent stability and performance under complex and harsh conditions (pH 2–10) and can be easily regenerated, confirming their excellent reusability and potential for practical applications.</p>