The synthesis and the electrochemical characterisation of new water soluble thiophene derivatives are reported. (3-Thenyl)triethylammonium bromide and (3-thenyl)triethylammonium Perchlorate were obtained by bromination of 3-methylthiophene and using the corresponding bromoderivative as alkylation agent in reaction with triethylamine in dry benzene. The new thiophene derivatives were characterised by 1-NMR, 13C-NMR, heteronuclear correlations experiments, and ESI-MS techniques. The electrochemical characterization of the new compounds has been performed in aqueous solution by means of cyclic voltammetry.