Poly(3,4-ethylenedioxythiophene) (PEDOT) doped with a new sulfonated derivate from bis(3,5-dimethylpyrazol-1-yl)methane (LSA) was electrochemically synthesized and characterized by cyclic voltammetry, chronoamperometry, scanning electron microscopy, Raman spectroscopy and ultraviolet/visible spectroscopy. In addition, LSA was also fully characterized. A PEDOT:LSA modified electrode was used to study the electrochemical detection of dopamine in the presence of ascorbic and uric acid. The use of this new dopant increased the sensitivity and reduced the detection limit compared with the values observed for PEDOT doped with perchlorate.