This contribution presents the asymmetrical modification of carbon microfibers (CMF) with gold and polythiophene, by bipolar electrochemistry (BPE) in acetonitrile (ACN). At first, the electrochemical behavior of AuCl4- in ACN was examined by cyclic voltammetry, in order to determine the deposition mechanism and the electric field threshold, beyond which bipolar electrochemistry allows metal deposition in such a medium. It is demonstrated that, by using suitable BPE conditions in ACN, it is possible to deposit asymmetrically species characterized by a difference in redox potential as high as 3 V. The modified CMFs are characterized by SEM, FEG-ESEM and EDS. (C) 2013 Elsevier Ltd. All rights reserved.