The chlorination and regeneration of poly(3-(4-fluorophenyl)thiophene) (PFPT) thin films has been investigated using cyclic voltammetry, energy dispersive analysis by X-ray, and X-ray photoelectron spectroscopy. A complete substitution of all 4-thiophene positions of the electrodeposited polymer is achieved by electrochemical oxidation in the presence of chloride ions. The resulting inactive chlorinated polymer is then reactivated by p-doping in acetonitrile containing 0.5 M Et4NBF4. The n-doping of this electroactive chlorinated polymer is not possible because the electrochemical reduction induces the departure of the chloride atoms, leading to the regeneration of the parent PFPT in the electroactive form.