Tetraphenyladamantane-based polyaminals with ultrasmall pore, large specific surface area and abundant CO2-philic aminal groups are successfully synthesized, which exhibit simultaneously high CO2 adsorption capacity of 17.6 wt % (4.0 mmol g(-1), 273 K/1.0 bar) and high adsorption selectivities of CO2/N-2 (104) and CO2/CH4 (24). Especially, at the low pressure, e.g., 0.15 bar, the CO2 uptake at 273 K can reach 8.7 wt 96 (1.97 mmol g(-1)). The adsorption/selectivity properties are superior to most of microporous organic polymers (MOPs) reported in the literature. Besides the outstanding CO2-capturing ability, the polymers also possess high uptakes of benzene and cyclohexane vapors up to 72.6 and 52.7 wt %, respectively. In addition, the effects of reaction activity and type of amino groups as well as the size and shape of building blocks on porous architecture of microporous polyaminals are studied. The disclosed results are helpful for the deep understanding of pore formation and interconnecting behavior in MOPs and therefore are of significant importance for the synthetic control of MOPs for a specific application in gas storage and capture of organic vapors.