The electrochemical detection of Ascorbic acid and dopamine is crucial due to their vital roles in biological processes. Both biomolecules coexist in the human body and have the same oxidation potential, leading to electrode fouling and overlapping of oxidation potential. Accurate detection enables monitoring their levels in biological samples, aiding in disease diagnosis and treatment. This study presents the fast and green synthesis of a highly sensitive and selective electrochemical biosensor for the simultaneous detection of dopamine and ascorbic acid. The change in spherical cluster morphology into nanorods enhances the electrode's electroactive surface area, enhancing sensor sensitivity and selectivity. Electrochemical characterization techniques, including cyclic voltammetry and electrochemical impedance spectroscopy, demonstrated excellent electron transportation and low charge transfer resistance. The sensor exhibited simultaneous detection with a low limit of detection of 8µM for dopamine and 6.9µM for ascorbic acid, with a wide linear working range. Additionally, the sensor showed excellent selectivity and repeatability with a vast potential gap at simultaneous detection, making it suitable for clinical and food industry applications.