Single site catalysts provide a unique platform for mimicking natural enzyme due to their tunable interaction between metal center and coordinated ligand. However, most works have focused on preparing structural and functional models of nature enzyme, with less reports also taking the local chemical environment, i.e., functional/catalytic residues around the active site which is an essential feature of enzymes, into consideration. Herein, we report a Co-centered porphyrinic polymer containing the enzyme-mimic micro-environment, where the linker triazole over CoN4 site enables formation of hydrogen bond with the *COOH intermediate, thus promoting the electrocatalytic reduction of CO2. As-prepared catalyst achieves the CO2-to-CO conversion of 5, 788 h−1 turnover frequency value and near unit (∼ 96%) faradaic efficiency at −0.61 V versus reversible hydrogen electrode. This strategy will bring new dimension of designing highly active single-site catalysts.