Along the development of ionic porous organic polymers, simple and efficient synthetic methods are actively pursued. Herein, the Debus–Radziszewski reaction is applied to synthesize ionic conjugated microporous polymers (iCMPs) in one step. A series of imidazolium-linked iCMP-X (X = 1, 2, 3) are developed for CO₂ sorption and in situ conversion with epoxide into cyclic carbonates. The as-synthesized iCMPs are characterized in detail by scanning electron microscope, solid-state nuclear magnetic resonance, X-ray photoelectron spectroscopy, X-ray diffraction analysis, N₂/CO₂ sorption, and more. Among all synthesized iCMPs, iCMP-1 possesses the highest specific surface area and in turn the strongest CO₂ sorption capacity. Moreover, through a simple anion ion exchange reaction with halide, iCMP-1 is transformed to iCMP-1@Cl that embodies significant catalytic capability for converting CO₂ into cyclic carbonates.