Syntheses of parent polyaniline and methyl, methoxy, and ethoxy ortho-substituted polyanilines were performed using the conventional chemical methodology and monitored using the new open-circuit-potential (V-oc) profile technique. The intermediate pernigraniline oxidation state was identified and isolated at the V-oc maximum (A) during the conventional chemical synthesis of poly(o-methoxyaniline) in the emeraldine oxidation state. The introduction of the substituent on the aniline ring leads to longer polymerization times and lower V-oc values. Syntheses in the presence of two different monomers in solution were also investigated and showed preferential polymerization of the monomer with the lowest V-oc potential. All polymers produced were characterized by elemental analysis, gel per meation chromatography, UV-VIS spectroscopy, and cyclic voltammetry. The influence of the substituent on the V-oc profile and on the polymer characteristics are rationalized in terms of steric and electronic effects.