N,N'-Bicarbazole with almost spatially vertical structure was synthesized by a facile method and was demonstrated as a versatile building block for conjugated microporous polymers (CMPs) through transition metal catalyzed coupling polymerizations including Yamamoto, Suzuki, and Sonogashira polymerizations. The porosities and morphologies of four N,N'-bicarbazole-based CMPs were systematically studied and compared. With high surface area, good thermal stability and microporous structure, the CMP synthesized by Yamamoto polymerization exhibited excellent adsorption capacities of CO2 and organic dyes, and the maximum adsorption capacity of methylene blue (MB) in water reached up to 1016 mg g-1. The good adsorption properties of N,N'-bicarbazole CMPs could be a good candidate for potential applications in water purification and treatment. [ABSTRACT FROM AUTHOR]