A bulk, template-free method to synthesize nanofibers Of Substituted polyanilines is presented. The morphology of the substituted polyanilines changes from agglomerates or micron-sized spheres to a nanofiber network when an initiator. such as p-phenylenediamine. is introduced into the conventional reagents used to synthesize these polymers. UV-vis spectroscopy and cyclic voltammetry reveal that the oxidation state and chemical composition of the substituted polyaniline nanofibers do not differ significantly from that of conventional polyaniline derivatives possessing an agglomerated morphology. Gel permeation chromatography indicates that the nanofibers; formed possess all unusually low polydispersity compared to substituted polyanilines synthesized by other methods. Open-circuit potential measurements obtained during the synthesis of these polyaniline derivatives confirm that there is a significant increase in the reaction rate of the polymerization which is directly related to nanofiber formation. This synthetic method appears quite general as a wide variety of substituted aniline monomers have been polymerized into nanofibrillar polymers.