Solution-processable microporous polymers are promising materials for CO2 capture because of their low synthetic cost and high processability. In this work, we for the first time systematically evaluate the feasibility of two microporous polymers, namely PIM-1 and its hydrolyzed form hPIM-1, as adsorbent materials for postcombustion CO2 capture. By conducting ternary CO2/N-2/H2O breakthrough experiments, PIM-1 demonstrates several promising features: moderate CO2 working capacity, low water vapor uptake capacity, good moisture resistance, and easy regeneration process. In addition, we have pioneeringly studied the multiple-cycle CO2 adsorption-desorption induced relaxation effect on soft PIM-1 polymers. Through a simple dissolution-precipitation approach, PIM-1 can restore its BET surface area, CO2 uptake capacity, and pore-size distribution. The solution reprocessability of PIM-1 demonstrated in this study distinguishes it from other rigid adsorbents and thus offers a new insight for the future design of economically-viable and facilely regenerable adsorbents. (c) 2018 American Institute of Chemical Engineers AIChE J, 64: 3376-3389, 2018