A new preparation of a polymer made from 5-hydoxy-2-methyl-1,4-naphthoquinone (plumbagin) is described. While conventional electropolymerization leads to self-limited growth of an inhibiting film, electropolymerization onto a grafted monolayer of plumbagin on glassy carbon (PLG/GC) yields continuous growth of a polymer film (polyPLG/PLG/GC). The electrochemical properties of polyPLG/PLG/GC have been intensively characterized by cyclic voltammograms (CVs) and showed the preservation of the redox chemistry of the quinone system within the polymer. The concentration of active site was almost five times higher than in the case of direct electropolymerization of plumbagin on GC (polyPLG/GC). The formal potential of the polyPLG/PLG/GC shifted with pH by 57 mV/pH unit up to pH 8 suggesting a two-electron/two-proton process. At higher pH, the slope decreased to 28 mV/pH unit pointing towards a two-electron/one-proton reaction. The pK(a) of the redox system was determined as 8.1. The electron-transfer rate constant and the transfer coefficient were determined to be k(s) = 12.5 s(-1) and alpha = 0.5 for polyPLG/PLG/GC in phosphate buffer solution pH 7. The surface morphology and thickness of polymer films were investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). This polyPLG/PLG/GC film showed an electrocatalytic response for oxygen reduction reaction (ORR) similar to a PLG/GC monolayer. This indicates as well as the CVs in oxygen-free solution the preservation of the quinone groups in the first monolayer. Both films were more effective than directly polymerized polyPLG film where the number of accessible quinone groups was much lower. (C) 2015 Elsevier Ltd. All rights reserved.