Direct coupling of carbenium ions with indoles and anilines for the synthesis of cationic π-conjugated dyes.

A C–C bond forming reaction occurs spontaneously between tris-(2,6-dimethoxyphenyl)carbenium ions and indoles/anilines. The carbocation acts both as an electrophile and an oxidant. Effective cationic π-conjugated dyes are formed resulting in a strong hyper- and bathochromism.