Abstract Polymethacrylic acid (PMAA) and modified Polymethacrylic acid functionalized with catechol (PMAA/CAT), hydroquinone (PMAA/HQ) and catechol-hydroquinone (PMAA/CAT-HQ) were synthesized by oxidative decarboxylation method using ammonium persulphate as an oxidant and characterized using UV–Visible spectroscopy, FT-IR, XRD, TGA and SEM studies. The percentage of substitution was found to be 81%, 84% and 87% respectively for PMAA/CAT, PMAA/HQ and PMAA/CAT-HQ. The anticorrosion behavior of the synthesized polymers on pure aluminium in 0.7 M HCl was studied by potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS) and weight loss (WL) methods. As the concentration of the inhibitor increases, the anticorrosion activities increases and reaches the optimum, on further increase in the inhibitor concentration, the anticorrosion activity decreased and remained constant that determines the optimum inhibition efficiency. The increase in the anticorrosion activities at the optimum inhibitor concentration of 300 ppm is found to be in the order: PMAA