Esterification and the consequent reduction of thiophene-3-acetic acid by lithium aluminum hydride produces 3-(2-hydroxyethyl)thiophene (2), which must be protected before anodic polymerization. Substance 2 and the protected compounds 3, 4, and 5 were investigated by multisweep cyclic voltammetry and characterized by their peak potentials. The poly[3-(2-methoxyethyl)thiophene] (6) prepared from 0.05 M monomer solution in acetonitrile by electrochemical polymerization via cyclic voltammetry (Delta E = 0-1.9 V [Ag/AgCl]) is the only electrically conducting polymer. Ether cleavage is carried out in the polymer film 6, and the resulting poly[3-(2-hydroxyethyl)thiophene] (7) reacts with various reagents. The obtained polymer derivatives are characterized by IR reflectance spectroscopy and by electrochemical methods. Polymer 7 is activated with cyanogen bromide to immobilize alcohol dehydrogenase at the surface of the electrode. It tvas found that the peak potentials of each polymer are characteristic for the appropriate polymer structures.