Supercapacitors have emerged as versatile energy storage devices, valued for their rapid charge-discharge capabilities and long cycle life. Concurrently, efficient electrocatalysts are essential for promoting the oxygen evolution reaction (OER) in sustainable energy applications. Inevitably, this study explores the integration of a Cobalt-Nickel (Co/Ni) based metal-organic framework [CoNi((μ 3 -tp) 2 (μ 2 -py) 2 or CNTP] with ZnFe 2 O 4 hollow spheres (ZHS) to create innovative CNTP/ZHS nanocomposites tailored for supercapacitor and electrocatalytic OER applications. Different weight percentages of CNTP/ZHS nanocomposites were synthesized through a facile and scalable method, and their electrochemical performance was rigorously assessed. Electrochemical characterization revealed that a 40 wt percentage CNTP/ZHS (40-CNTP/ZHS) electrode demonstrated a very high specific capacitance of 1519.2 Fg−1 at 1 Ag−1 and retained 92.6 % of its specific capacitance after 10000 cycles. Moreover, it delivered remarkably high specific capacitance (447.2 Fg−1) and energy density (62.1 WhKg−1) along with outstanding cyclic stability (97.5 % after 5000 galvanostatic charge-discharge cycles). It also exhibited excellent OER activity, with a very low overpotential (207 mV to attain a current density of 10 mAcm−2), a small Tafel slope (66.5 mVdec−1), and high stability over 2000 cyclic voltammetry cycles. These characteristics underscore the significant potential of renewable energy technologies, particularly for water electrolysis and sustainable energy conversion. 1 1 OER, oxygen evolution reaction; tp, terephthalic acid; pyz = pyrazine; CNTP, CoNi((μ 3 -tp) 2 (μ 2 -pyz) 2 ; ZHS, ZnFe 2 O 4 hollow spheres; MOF, metal-organic framework; RHE, reversible hydrogen electrode; PEG-600, polyethylene glycol 600; EIS, electrochemical impedance spectroscopy; GCD, galvanostatic charge-discharge; CV, cyclic voltammetry; PVDF; polyvinylidene fluoride; NMP, N -methyl-2-pyrrolidone; SSC, symmetric supercapacitor; LSV, linear sweep voltammetry; ECSA, electrochemical active surface area; XRD, X-ray diffraction; EDS, energy-dispersive spectroscopy; XPS, X-ray photoelectron spectroscopy; FWHM, full width at half maximum; FTIR, Fourier-transform infrared; DRS, diffusion reflectance spectroscopy; FE-SEM, field emission scanning electron microscopy; FE-TEM, field emission transmission electron microscopy; HR-TEM, high-resolution transmission electron microscopy; XPS, X-ray photoelectron spectroscopy; PL, photoluminescence; ASC, asymmetric supercapacitor. [Display omitted] • CNTP/ZHS nanocomposites synthesized for OER and supercapacitor applications. • 40-CNTP/ZHS electrode exhibits high specific capacitance (1519.2 Fg−1). • Outstanding cyclic stability (92.6 % retention after 10000 cycles). • Symmetric supercapacitor with 40-CNTP/ZHS achieves high energy density (62.1 WhKg-1). • Low OER overpotential (207 mV for 10 mAcm–2), small Tafel slope (66.5 mVdec–1). [ABSTRACT FROM AUTHOR]