This study reports the synthesis and characterization of a hetero-diatomic CoN4-NiN4 catalyst on nitrogen-doped carbon, which exhibits superior bifunctional activity for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline solution. The catalyst is prepared through the controlled pyrolysis of ZIF-8 containing Co2+ and Ni2+ species. Experimental and theoretical analyses reveal that Co and Ni atoms are atomically dispersed in pairs with an intersite distance of approximately 0.41 nm, and there is long-range d-d coupling between the metals, leading to enhanced electron delocalization and bifunctional activity. The catalyst also features in situ grown carbon nanotubes at the edges of the catalyst particles, enhancing electronic conductivity. Electrochemical evaluations show that the Co/Ni-NC catalyst has a narrow potential gap of 0.691 V and long-term durability, outperforming single-atom Co-NC and Ni-NC catalysts, as well as benchmark Pt/C and RuO2 catalysts. When used in Zn-air batteries, the Co/Ni-NC catalyst achieves a high specific capacity of 771 mAh g−1 and a continuous operation period of up to 340 hours with a small voltage gap of approximately 0.65 V, surpassing the performance of Pt/C-RuO2. Theoretical calculations further elucidate the synergistic effects of the hetero-diatomic site pairs on improving the ORR and OER activities.This study reports the synthesis and characterization of a hetero-diatomic CoN4-NiN4 catalyst on nitrogen-doped carbon, which exhibits superior bifunctional activity for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline solution. The catalyst is prepared through the controlled pyrolysis of ZIF-8 containing Co2+ and Ni2+ species. Experimental and theoretical analyses reveal that Co and Ni atoms are atomically dispersed in pairs with an intersite distance of approximately 0.41 nm, and there is long-range d-d coupling between the metals, leading to enhanced electron delocalization and bifunctional activity. The catalyst also features in situ grown carbon nanotubes at the edges of the catalyst particles, enhancing electronic conductivity. Electrochemical evaluations show that the Co/Ni-NC catalyst has a narrow potential gap of 0.691 V and long-term durability, outperforming single-atom Co-NC and Ni-NC catalysts, as well as benchmark Pt/C and RuO2 catalysts. When used in Zn-air batteries, the Co/Ni-NC catalyst achieves a high specific capacity of 771 mAh g−1 and a continuous operation period of up to 340 hours with a small voltage gap of approximately 0.65 V, surpassing the performance of Pt/C-RuO2. Theoretical calculations further elucidate the synergistic effects of the hetero-diatomic site pairs on improving the ORR and OER activities.