Copper-doped magnesium di-boride (Cu–MgB<inf>2</inf>) superconductor is used for the first time as an electroactive iodide ion sensing material in a potentiometric iodide ion selective electrode. Un-doped and Cu-doped MgB<inf>2</inf> membranes (5 % and 10 % Cu) are synthesized via a solid-state reaction and fully characterized using XRD, FE-SEM/EDS, and EIS methodology. Comparative analysis reveals that 5 % Cu-doping significantly enhances the surface roughness, reduces charge-transfer resistance, and improves the potentiometric performance characteristics. Electrode based on Cu–MgB<inf>2</inf> (5 % Cu dopant) exhibits a Nernstian slope of −59.51 ± 0.4 mV/decade over a linear iodide concentration range of 4.53 × 10⁻⁷ to 6.18 × 10⁻³ mol/L and a low detection limit of 1.44 × 10⁻⁷ mol/L (18.27 ppb). The response time is less than 6 s, and more than 98 % of the original calibration slope is retained over 50 days. Electrochemical impedance spectroscopic (EIS) measurements display a reduced charge transfer resistance (R<inf>ct</inf> = 171.1 Ω) and a high constant phase element (15.16 μS·sⁿ). The electrode demonstrates good selectivity over most common anions and a stable potential response over the pH range of 3.8–6.0. Method validation was performed according to the international guidelines (FDA, AOAC, USEPA, USP), and quality control/quality assurance studies confirm the accuracy, precision, trueness, within-day repeatability, between-days reproducibility, long term stability and robustness. The electrode is satisfactorily used for the determination of iodide and/or iodine in some pharmaceutical formulations. The results compare favourably with data obtained using the standard methods.