Cobalt nickel oxide nanoparticles (CNO Np) were synthesized using a combustion method with cobalt nitrate, nickel nitrate, and D-Glucose in equal concentration. The Np were characterized using XRD, FTIR, SEM, EDAX, and elemental mapping. The CNO Np was then deposited on a glassy carbon electrode through electro polymerization to prepare CNO Np/MGCE. Electrochemical responses of analytes at the modified electrode were investigated using cyclic and differential pulse voltammetry. Distinct oxidation peaks for guanine (GU) and uric acid (UA) were observed in a phosphate-buffered electrolyte at neutral pH. The electrode process was studied by varying the scan rate, allowing determination of the electrochemical behaviour. Limits of detection and quantification for GU and UA were evaluated by altering analyte concentrations. Additionally, pH-dependent studies using cyclic voltammetry provided insight into the proton-to-electron ratio involved in the redox process. Overall, the CNO Np/MGCE exhibited high sensitivity and selectivity for the simultaneous detection of GU and UA, demonstrating its potential as an effective electrochemical sensor for these biomolecules.