The　electrochemical　oxidative　functionalization　of　benzylic　C　H　bonds,　mediated　by　a　dual　bromide　ion/2,2,6,6-tetramethylpiperidinyl-N-oxyl　(TEMPO)　redox　catalyst　system　in　a　two-phase　electrolytic　medium,　has　been　explored　using　cyclic　voltammetry　(CV)　and　preparative　electrolysis　techniques.　The　results　show　that　electron　transfer　between　TEMPO+　and　a　neutral　substrate　occurs　with　an　efficiency　that　depends　upon　the　presence　of　a　base.　The　preparative　scale　electrolysis　led　to　the　formation　of　dihydro-isoquinolinones,　isochromanone　and　xanthenone　in　moderate　to　excellent　yields.　On　the　basis　of　the　CV　analysis　and　preparative　electrolysis　results,　a　reaction　mechanism　is　proposed.　(C)　2013　Elsevier　Ltd.　All　rights　reserved.