Highly selective adsorption of CO over CO 2 in a Cu(I)-chelated porous organic polymer.

•Cu(I) species were stably chelated to nitrogen atoms in SNW-1 by mixing with a CuCl solution.•Cu(I)-chelated SNW-1 shows selective CO adsorption over CO2 due to the π-complexation of CO with Cu(I).•1.3Cu(I)@SNW-1 exhibits good cyclic CO/CO2 separation performances under dynamic mixture flow conditions.•1.3Cu(I)@SNW-1 exhibits a good stability under exposure to atmospheric air.