Abstract Electrochromic films of poly(2,3,5,6-tetrafluoroaniline) (PTFA) were formed on ITO substrates from aqueous solutions utilising perchloric acid (HClO4) as dopant. Electrochemical and spectroscopic characterization of PTFA films was performed in background electrolyte and in solutions with the addition of tetrahydrofuran. When the PTFA film was removed from its growth medium, a significant decrease in the faradaic current was observed. The faradaic response increased on addition of tetrahydrofuran which facilitates ion movement through the polymer matrix. PTFA films deposited on ITO substrate were orange and light orange in the oxidized and reduced forms, respectively. The films were ca. 25nm in thickness. In aqueous solution the films showed a porous structure with a non-uniform distribution of pore diameters. In the presence of tetrahydrofuran a less porous structure was observed.