<p>Developing electrode materials with integrated functionality for electrochemical sensing and energy storage is critical to advancing wearable and portable electronics. In this study, a nitrogen and sulfur co-doping approach was employed to tailor the physicochemical properties of graphene for multifunctional applications. The co-doped graphene exhibited a surface area of 236 m2/g, high defect density, and improved electrical conductivity, enabling effective ion transport and charge storage. Structural characterization confirmed successful incorporation of both dopants and induced disorder within the carbon lattice. Electrochemical measurements demonstrated combined sensing and capacitive behavior. For sensing applications, the material showed a linear detection range of 1–150 µM for hydroquinone with a detection limit of 0.28 µM. These characteristics were attributed to the redox-active sulfur functionalities and conductive nitrogen domains that enhanced analyte adsorption and electron transfer. In energy storage tests, the co-doped graphene electrode exhibited a specific capacitance of 280 F/g at 1 A/g, with an energy density of 42 Wh/kg and 95% capacitance retention after 10,000 cycles. These results suggest that the synergistic effects of nitrogen and sulfur co-doping modify graphene’s electronic structure and interfacial chemistry in a manner beneficial to both applications. The adopted synthesis method—based on hydrothermal doping and thermal annealing—is scalable and environmentally benign. This study underscores the feasibility of employing co-doped graphene as a metal-free platform for integration into compact electronic systems requiring combined sensing and energy storage functionalities.</p>