The potential to produce high-purity C 2 H 4 has made ethyleneselective adsorbents for ethane (C 2 H 6 )/ethylene (C 2 H 4 ) gas mixture separation appealing as viable substitutes for traditional cryogenic distillation. In this aspect, porous organic polymers (POPs) are anticipated to become the next-generation potential adsorbent due to their easily customizable functions and functional sites suitable for gas separation. This article reports the selective C 2 H 4 adsorption over C 2 H 6 using microporous copper(I)-coordinated POP (Cu@Di-POP) via fine-tuning of the π complexation and pore size. The specially designed adsorbent has the ideal pore size and coordinated Cu(I) ions to form π-complexation with C 2 H 4 molecules, which enabled it to adsorb C 2