An increased emphasis on alternative energy technologies paves the way for the design and development of highly active, cost-effective electrocatalysts for application in water splitting and fuel cells. In lieu of this, we evaluated heterostructured copper selenide and zinc selenide enwrapped in carbon nanofibers (CZSe@C-450) as bifunctional electrocatalysts synthesized by electrospinning and selenization. CZSe@C-450 demonstrated superior electrochemical performance with a low overpotential of 260 mV at 10 mA cm−2, high stability (1.2% loss in 12 hours and 9.9% loss in 50 hours) for oxygen evolution reaction, a half-wave potential (E1/2) of 0.88 V, and high stability (14.35% loss in 50 hours) for oxygen reduction reaction. The enhanced performance is attributed to the formation of a heterogeneous phase boundary between copper selenide and zinc selenide, which increases both the built-in potential and local atomic disorder. The lattice mismatch/disorder reduces the surface energy and leads to the creation of an ample number of active sites that participate in both oxygen evolution and reduction reactions. © 2022 The Royal Society of Chemistry.