CO2 adsorption and concomitant catalytic conversion into useful chemicals are promising approaches to alleviate the energy crisis and effects of global warming. This is highly desirable for developing new types of heterogeneous catalytic materials containing CO2 -philic groups and catalytic active sites for CO2 chemical transformation. Here, we present an imidazolium- and triazine-based porous organic polymer with counter chloride anion (IT-POP-1). The porosity and CO2 affinity of IT-POP-1 may be modulated at the molecular level through a facile anion-exchange strategy. Compared with the post-modified polymers with iodide and hexafluorophosphate anions, IT-POP-1 possesses the highest surface area and the best CO2 uptake capacity with excellent adsorption selectivity over N2 . The roles of the task-specific components such as triazine, imidazolium, hydroxyl, and counter anions in CO2 absorption and catalytic performance were illustrated. IT-POP-1 exhibits the highest catalytic activity and excellent recyclability in solvent- and additive-free cycloaddition reaction of CO2 with epoxides.