Microporous organic polymers (MOPs) are porous materials. Owing to their high surface area, tunable pore sizes and high physicochemical stability, they are studied for applications including gas capture and separation and heterogeneous catalysis. In this thesis, a series of imine/azo-linked MOPs were synthesized. The MOPs were examined as potential CO₂ sorbents and as supports for heterogeneous catalysis.

The MOPs were synthesized by Schiff base polycondensations and oxidative couplings. The porosities of the imine-linked MOPs were tunable and affected by a range of factors, such as the synthesis conditions, monomer lengths, monomer ratios. All the MOPs had ultramicropores and displayed relatively high CO₂ uptakes and CO₂-over-N₂ selectivities at the CO₂ concentrations relevant for post-combustion capture of CO₂. Moreover, the ketimine-linked MOPs were moderately hydrophobic, which might increase their efficiency for CO₂ capture and separation.

The diverse synthesis routes and rich functionalities of MOPs allowed further post-modification to improve their performance in CO₂ capture. A micro-/mesoporous polymer PP1-2, rich in aldehyde end groups, was post-synthetically modified by the alkyl amine tris(2-aminoethyl)amine (tren). The tethered amine moieties induced chemisorption of CO₂ on the polymer, which was confirmed by the study of in situ infrared (IR) and solid-state ¹³C nuclear magnetic resonance (NMR) spectroscopy. As a result, the modified polymer PP1-2-tren had a large CO₂ capacity and very high CO₂-over-N₂ selectivity at low partial pressures of CO₂.

Pd(II) species were incorporated in the selected MOPs by means of complexation or chemical bonding with the imine or azo groups. The Pd(II)-rich MOPs were tested as heterogeneous catalysts for various organic reactions. The porous Pd(II)-polyimine (Pd²⁺/PP-1) was an excellent co-catalyst in combination with chiral amine for cooperatively catalyzed and enantioselective cascade reactions. In addition, the cyclopalladated azo-linked MOP (Pd(II)/PP-2) catalyzed Suzuki and Heck coupling reactions highly efficiently.