A new ultramicroporous conjugated network, P-TCzTAT, enriched with propeller-like carbazole building blocks was designed and synthesized by FeCl3 oxidative coupling polymerization at room temperature. The adsorption isotherm of N2 reveals that the polymer features a high Brunauer–Emmett–Teller (BET) specific surface area of 1028 m2 g−1 and a predominantly narrow pore width of 0.54 nm. The ultramicroporous polymer has strong affinity for CO2, with high sorption abilities of 18.15% at 273 K and 1.1 bar and 10.69% at 273 K/1.1 bar and 298 K/1.1 bar, which can be ascribed to not only its optimal fraction of ultramicropores but also its high nitrogen content derived from the carbazole components. P-TCzTAT also exhibited potential application in gas storage and in CO2/CH4 and CO2/N2 gas separation.
