<p>The widespread discharge of synthetic dyes into aquatic environments poses a serious threat to water quality and public health, necessitating the development of rapid and sensitive analytical methods for their monitoring. In this work, an efficient electrochemical sensor was developed for the simultaneous detection of methylene blue (MB) and rhodamine B (RhB) using a MnO₂ nanorod-modified glassy carbon electrode (α-MnO₂/GCE). The electrochemical sensing performance of the modified electrode was systematically evaluated using cyclic voltammetry and differential pulse voltammetry, with both dyes exhibiting distinct, well-resolved electrochemical responses. Owing to the enhanced electroactive surface area and accelerated electron-transfer kinetics imparted by the MnO₂ nanorods, the sensor demonstrated excellent analytical sensitivity and low detection limits of 0.10 µM for MB and 0.56 µM for RhB, with sensitivities of 3.92 and 2.0 µA µM^-1 cm^-2, respectively. The developed sensing platform further showed reliable applicability toward the analysis of contaminated water samples. These findings demonstrate that MnO₂ nanorods are promising functional nanomaterials for the simultaneous electrochemical determination of hazardous organic dyes and offer a viable strategy for efficient water quality assessment.</p>