The　performance　of　organic　electrical　devices　is　highly　dependent　on　the　oxidation　potential　(E-OX)　and　the　reduction　potential　(E-RED)　of　the　used　materials.　To　develop　a　generalized　method　for　predicting　the　redox　potentials　of　organic　semiconductors,　we　assess　the　performance　of　13　density　functionals　(Le.,　PBE,　BLYP,　B3LYP,　PBE0,　M06,　M062X,　M06HF,　CAM-B3LYP,　omega　B97,　omega　B97X,　omega　B97XD,　LC-omega　PBE*　and　B2PLYP)　for　estimating　the　E-OX　and　E-RED　of　50　compounds　used　in　organic　light-emitting　diodes　on　the　basis　of　thermodynamic　cycles　for　electron　transfer.　In　comparison　with　the　experimental　data　measured　by　cyclic　voltammetry,　the　combination　of　PBE0　with　def2TZVP　basis　set　and　B3LYP　or　M06　with　6-311　+　+G　(d,　p)　basis　set　is　found　to　give　reliable　E-ox　and　E-red　with　a　mean　absolute　error　of　0.05　V　and　0.08　V,　respectively.　The　correlations　between　the　theoretical　frontier　orbital　energies　and　the　measured　redox　potentials　are　also　investigated.