Adsorption process is a cost‐effective way to the dye removal and CO₂ capture. Improvements of the adsorption performance and conformance to the practical application conditions are necessary steps to approach practicality. Herein, hierarchical porous carbon‐doped boron nitride (BCN) aerogels with amino modification were synthesized for the first time by freeze drying and carbothermal reduction method. As‐prepared BCN aerogels exhibited superior adsorption performance for CO₂ and dyes. Compared with BN aerogel, notwithstanding the lower surface area, the as‐prepared BCN aerogel exhibited 6‐fold‐enhanced CO₂ capture and higher dyes adsorption capacity, delivering a more than 150 times adsorption rate with methylene blue (MB) as the adsorbent. The reinforced adsorption properties were demonstrated to be primarily from the synergistic effect of carbon doping and amino decoration on the obviously improved adsorption energy, hydrophilicity and mesopore volume, accelerating the kinetics of dye and gas molecules diffusion. This work provides a new way on the design of high‐efficiency absorbent materials.