A ratiometric electrochemical sensor featuring a benzoquinone-modified vertically aligned mesoporous silica film (BQ/VMSF) has been developed for the accurate detection of diclofenac (DCF), a widely utilized non-steroidal anti-inflammatory drug. The design process employed the Electrochemical assisted self-assembly (EASA) technique to grow a thiol-functionalized mesoporous silica film on a carbon screen-printed electrode, which was further modified with benzoquinone via click chemistry. Characterization using Transmission Electron Microscopy (TEM), Fourier-Transform Infrared Spectroscopy (FTIR), Cyclic Voltammetry (CV), and Electrochemical Impedance Spectroscopy (EIS) confirmed the successful synthesis and optimal functionality of the mesoporous structure. In this configuration, benzoquinone serves as an internal redox reference, generating one redox signal, while the electrochemical oxidation of diclofenac produces a second redox signal. The sensor's output is derived from the ratio of these two signals, I