A novel compound, [Ni(DCPTP)] n (termed Ni-DCPTP), based on the 4'-(3,5-dicarboxyphenyl)-2,2',6',2″-terpyridine (DCPTP2-) ligand was presented here. Ni-DCPTP has a three-dimensional structure with a ths topology featuring one-dimensional (1D) helical channels. Ni-DCPTP shows an efficient removal of a trace amount of C2H2 from a C2H2/C2H4 (1/99) mixture with an excellent C2H4 productivity as demonstrated by both the transient breakthrough simulations and breakthrough experiments, generating the polymer-grade C2H4 gas (C2H2 < 40 ppm). The carboxylate oxygen atoms on the surface of 1D channels are the preferential binding sites for C2H2 molecules. This work demonstrates an elegant example with carboxylate oxygen-functionalized pore channels for effective C2H2/C2H4 separation.