The present study reports the preparation of two different semiconducting polythiophene-type polymers, poly(hydroxymethylated-3,4-ethylenedioxythiophene), (PEDOT-MeOH) and poly[2,2’-(3-dodecylacetate)thiophene], (P3TDA). PEDOT-MeOH was electrochemically synthesized and P3TEA was chemically prepared and electrochemically doped afterwards, in order to be used as biosensors for biomolecules. Structural and microstructural properties were characterized by Fourier Transform Infrared (FTIR) and UV-visible-near spectroscopies, atomic force microscopy (AFM) and scanning electronic microscopy (SEM). On the other hand, thermal properties were analyzed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). PEDOT-MeOH supported on ITO electrodes presented a good response for the detection and discrimination of dopamine, uric acid and ascorbic acid incorporated in the same aqueous solution (0.1mM, 0.1mM and 0.2mM, respectively). P3TDA, instead, was able to detect dopamine (0.1mM) supported on glassy carbon microelectrodes. In spite of the insertion of a long pendant aliphatic chain into the structure of the polymer, solubility wasn’t successfully improved, obtaining only a polymer partially soluble in organic solvents, like chloroform, tetrahydrofuran or toluene