An acid-induced conversion method for dithiocarbamate precursor poly(thienylenevinylene) (PTV) and poly(phenylenevinylene) (PPV) derivatives is presented, which has the advantage that it can be executed at moderate temperatures. The lower conversion temperature avoids possible thermal degradation of the polymer chromophore structure, and therefore conjugated polymers with a higher effective conjugation length can be obtained. This process was studied using UV-vis and FTIR spectroscopy. The obtained results indicate that trifluoroacetic acid yields a more defect-free structure as compared to benzenesulfonic acid which induces degradation after prolonged reaction times. A tentative mechanism is proposed in which the formation of an intermediate carbenium ion is part of the rate-limiting step. It also implicates a competition between elimination and substitution reactions depending on specific reaction conditions.