 This study synthesized planar symmetry broken copper nitride, PSB, CUN3, single atom catalysts through microwave heating and found that they exhibited a higher selectivity towards formate in electrocatalytic CO2 reduction compared to symmetrical CUN4 catalysts. The study revealed that the intrinsic local symmetry breaking from planar D4H configuration induced an unconventional DSP hybridization, which correlated with the microenvironment of metal center, coordination number and distortion, leading to high preference for formate production in CUN3 moiety. This finding opens an avenue for designing efficient single atom catalysts with specific local symmetries for selective electric catalysis. This article was authored by Juansai Dong, Yangyang Liu, Jiajing Pei, and others.