In this paper, we report the electrochemical polymerization of 3-decylthiophene at room temperature using the l-butyl-3-methylimidazoliumtetrafluorborate as solvent. The polymer film is electroactive and its morphology depends upon the anode used. The polymerized 3-decylthiophene was characterized by ft-infrared, uv-visible, thermal gravimetric analysis and conductivity measurement