We studied polydithieno[3,4-b : 3’,4’-d]thiophene (pDTT), an electronically conducting polymer with a narrow band gap, and our data clearly demonstrated that the charge injection of both signs is possible in electrolytic media with tetraalkylammonium salts. This is an important feature for the development of polymer-based redox supercapacitors with high charge storage capacity and high operating potential. Electrochemical characterization data of p- and n-doped pDTT films electrosynthesized in different conditions and on several electrode materials are reported. Successful results were achieved on carbon paper electrodes where the same p- and n-doping levels were reached.