The stepwise electrochemical oxidation of p-methoxyphenol and hydroquinone at boron-doped diamond (BDD) electrodes was investigated in perchloric acid media using rotating ring-disk electrode (RRDE) and hydrodynamic modulation techniques, Initial oxidation of these compounds top-benzoquinone at the disk may be confirmed by reduction of the quinone at the ring electrode. Further oxidation, ultimately to CO2, can be followed by the loss of redox active products at the ring. Comparison of BDD anodic activity to those of graphite, gold, and platinum electrodes, utilizing RRDE configurations, shows that the high oxygen evolution overpotential exhibited by BDD allows for more efficient anodic conversion of p-methoxyphenol and hydroquinone to products beyond the quinone stage. BDD, unlike the other electrode materials, showed no corrosion or fouling when used under these conditions. These results complement product analysis studies by other groups on BDD for organic contaminant remediation by exhaustive electrolysis.