Manipulation of selectivity in the catalytic electrochemical carbon dioxide reduction reaction (eCO 2 RR) poses significant challenges due to inevitable structure reconstruction. One approach is to develop effective strategies for controlling reaction pathways to gain a deeper understanding of mechanisms in robust CO 2 RR systems. In this work, by precise introduction of 1,10-phenanthroline as a bidentate ligand modulator, the electronic property of the copper site was effectively regulated, thereby directing selectivity switch. By modification of [Cu 3 (btec)(OH) 2 ] n , the use of [Cu 2 (btec)(phen) 2 ] n ·(H 2 O) n achieved the selectivity switch from ethylene (faradaic efficiency (FE) = 41%, FE C2+ = 67%) to methane (FE CH 4 = 69%). Various in situ spectroscopic characterizations revealed that [Cu 2 (btec)(phen) 2 ] n ·(H 2 O) n promoted the hydrogenation of *CO intermediates, leading to methane generation instead of dimerization to form C 2+ products. Acting as a delocalized π-conjugation scaffold, 1,10-phenanthroline in [Cu 2 (btec)(phen) 2 ] n ·(H 2 O) n helps stabilize Cu δ+ . This work presents a novel approach to regulate the coordination environment of active sites with the aim of selectively modulating the CO 2 RR.