<p>An electrochemical sensor for dimethyl phthalate (DMP) on electrochemically transformed copper benzene tricarboxylate (Cu-BTC) metal-organic framework (MOF)&#xa0;was developed. The MOF has been electrochemically activated by cycling on glassy carbon electrode (GCE) surface in presence of graphene oxide (GO) to yield Cu(OH)₂@Cu-BTC-rGO and utilised for sensing of DMP. Physiochemical characterization has been carried out to understand the nature of the composite and electrochemical transformation of Cu-BTC has been investigated in various electrolytes with respect to sensing performance. Sensing behaviour of Cu(OH)₂@Cu-BTC-rGO towards DMP in polyethylene terephthalate (PET) bottled water was analysed using cyclic voltammetry and differential pulse voltammetry. Ex-situ analysis such as NMR, UV-Vis and EPR spectroscopy analyses confirmed that DMP detection was due to the cation-π interaction between Cu¹⁺/Cu²⁺ ions present in composite and the benzene ring of DMP. This interaction resulted in the change in current with respect to DMP concentration in the range of 1 µM to 500 µM with a detection limit of 0.17 µM (R² 0.9870), well below the threshold range (<i>10.3 µM</i>) provided by U.S. Environmental Protection Agency (EPA). The results from electrochemical method employed to quantify the DMP in real environment were validated with conventional HPLC analysis.</p> Graphical Abstract <p></p>