A series of highly conductive and electroactive fluorine-functionalized polyanilines (F-Pans) (containing 28-131 mol % of F) have been successfully prepared via the concurrent reduction and substitution (CRS) method, by reacting the polyaniline emeraldine base with tetrabutylammonium fluoride in MeOH for 12 h. Although the conventionally prepared poly(fluoroaniline)s were in general found to be poorly conductive (10(-6)-10(-5) S/cm) with lowered molecular weights (4 x 10(3)), significantly blue-shifted UV-vis absorption (with the exciton band appearing at 362-555 nm), and greatly increased oxidation potential (similar to 0.42 V vs SCE in 1 M HCl) in comparison with the similarly prepared unsubstituted polyaniline, the F-Pans obtained from the CRS method are not only highly conductive (3-0.1 S/cm) but also very much electroactive, with molecular weight, UV-vis absorption lambda(max), and oxidation potentials comparable to those of the parent unsubstituted polyaniline. Such interesting new results accompanied with the CRS-prepared F-Pans suggest that the electronegativity of the F group alone could not be solely responsible for the poor conductivity associated with the conventionally prepared poly(fluoroaniline)s.