A series of hydroxyl-rich crown ether-based organic polymers chelating potassium iodide were constructed via a phenolic–condensation reaction and characterized, which were immediately applied to CO₂ fixation reactions and iodine vapor adsorption. CHOP@KIs possess micropores and a specific surface area of only 5.16 m² g⁻¹; however, experimental results manifested that the polymer has good catalytic properties and iodine vapor adsorption capacity. CHOP@KI-1 catalyzed the CO₂ cycloaddition reaction with a conversion rate of up to 97.5% under ideal reaction conditions and exhibited good recyclability and outstanding substrate fitness. From the kinetics, the activation energy was calculated to be 56.55 kJ mol⁻¹. Furthermore, the iodine capture property of CHOP@KIs was investigated, and the adsorption capacities were 1.47 g g⁻¹, 1.38 g g⁻¹ and 1.60 g g⁻¹ respectively. The kinetics of iodine adsorption by CHOP@KIs followed a pseudo-first-order model and the initial stage of adsorption is controlled by membrane diffusion.