The increasing CO2 concentration in the atmosphere contributes significantly to global warming, necessitating effective capture techniques. Though amine‐based solvents are commonly used, they have drawbacks like high energy consumption and corrosion. Physical adsorption using microporous sorbents with polar groups emerges as a promising alternative, offering high efficiency and selectivity for CO2 capture. This work presents the design of a new microporous hypercrosslinked polymer with amino groups derived from the 3D molecular building block triptycene (TBMP‐NH2), for CO2 capture applications. The triptycene unit in the polymer backbone provides high surface area, thermal stability, and microporosity. TBMP‐NH2 demonstrates excellent thermal stability (Td > 350°C), considerable microporosity, and a high BET‐specific surface area of 866 m2/g, making it a promising microporous adsorbent. It exhibits a high CO2 adsorption capacity of 1.86 mmol/g at 273 K and 1.23 mmol/g at 298 K, with a Qst value of 33.95 kJ/mol, indicating a physisorption mechanism where the micropore volume (Vmic = 0.359 cm3/g) plays a crucial role. TBMP‐NH2 displays good CO2/N2 and CO2/CH4 selectivity, outperforming several reported porous polymers. Owing to its high physiochemical and thermal properties, and efficient and selective CO2 capture ability, TBMP‐NH2 can be considered a promising material for CO2 capture and environmental remediation application.