In　this　paper,　the　relationship　between　the　electrochemical　characteristics　and　the　structure　of　a　series　of　substituted　phenol　derivatives　with　electron-donating　or　electron-withdrawing　groups　were　studied　by　voltammetry　using　ordered　mesoporous　carbons　(OMCs)　modified　glassy　carbon　electrode　(GCE)　(OMCs/GCE).　p-Nitrophenol　(p-NP)　and　p-methylphenol　were　selected　as　models　of　electron-withdrawing　and　electron-donating　groups,　respectively,　to　illustrate　the　electrochemical　behavior　and　reaction　mechanism　of　substituted　phenols.　Voltammetric　study　showed　that　the　oxidation　peak　potential　(E-pa)　of　substituted　phenols　with　an　electron-withdrawing　group　was　systematically　higher　than　that　of　substituted　phenols　with　an　electron-donating　group.　That　is,　the　direct　electrochemical　oxidation　of　substituted　phenol　with　an　electron-withdrawing　group　is　more　difficult　than　that　of　substituted　phenol　with　an-electron-donating　group.　The　E-pa　value　shifted　negatively　with　the　increase　of　pica　for　both　p-substituted　phenols　and　o-substituted　phenols　with　the　equations　of　pKa　=　-6.986　E-pa　+　13.261　(for　p-substituted　phenols)　and　pKa　=　-7.929　E-pa　+　13.831　(for　o-substituted　phenols).　Thus,　a　simple　and　novel　method　was　proposed　for　the　precise　prediction　of　the　pKa　of　substituted　phenols　by　determining　E-pa　values　with　voltammetry　at　OMCs/GCE,　which　matched　fairly　with　the　results　calculated　from　Hammett＇s　constants.　Thus,　the　present　work　may　provide　additional　strategy　to　determine　pKa　values　and　investigate　possible　mechanisms　of　some　organic　reactions.　In　addition,　by　making　use　of　the　substituent　effect,　different　p-substituted　phenols　(or　o-substituted　phenols)　can　be　well　separated　and　identified　at　OMCs/GCE　by　voltametry,　which　may　find　possible　applications　in　simultaneous　detection　of　p-substituted　phenols　(or　o-substituted　phenols).　(C)　2013　Elsevier　Ltd.　All　rights　reserved.