The protonation of certain triarylamines and two N-arylcarbazoles with trifluoromethanesulfonic acid yields, besides of N-protonated species with ammonium salt structure, C-substituted iminium salts with a cylohexa-1,2- or 1,4-diene structure also. The last mentioned compounds could be detected in some cases only by deuteration experiments. Whereas the C-substituted iminium salts are formed with triphenylamine and 1-(N,N-diphenyl)in a very low extent, they are formed with other naphthylamine and carbazole derivates in higher yields. In accordance with this finding, all per-aryl substituted amines studied could be transformed by reaction with deuterated trifluormethanesulfonic acid into C-deuterated species with different deuterium content.