We presented the immobilization of ionic liquids on the channel walls of COFs using a post-synthetic strategy. The ionic [Et4NBr]50%-Py-COF afforded a high CO2 adsorption capacity of 164.6 mg g(-1) (1 bar, 273 K) and was developed as an effective heterogeneous catalyst for the transformation of CO2 into value-added formamides under ambient conditions.

Two structurally similar groups with one being CO2-philic but the other not were anchored into the channel walls of 2D COFs. The decreased surface area of COFs undoubtedly decreased CO2 adsorption if too many functional groups were introduced.