Electrochemical oxidation represents an environmentally friendly solution to conventional methods that require caustic stoichiometric chemical oxidants.However,C-H functionalizations merging transition-metal catalysis and electrochemical techniques are,to date,largely confined to the use of precious metals and divided cells.Herein,we report the first examples of copper-catalyzed electrochemical C-H aminations of arenes at room temperature using undivided electrochemical cells,thereby providing a practical solution for the construction of arylamines.The use of n-Bu4NI as a redox mediator is crucial for this transformation.On the basis of mechanistic studies including kinetic profiles,isotope effects,cyclic voltammetric analyses,and radical inhibition experiments,the reaction appears to proceed via a single-electron-transfer(SET)process,and a high valent Cu(Ⅲ)species is likely involved.These findings provide a new avenue for transition-metal-catalyzed electrochemical C-H functionalization reactions using redox mediators.