alkanesulfonates) (P3TAS's) containing propanesulfonate, hexanesulfonate, and octanesulfonate substituents have been prepared by oxidative coupling using ferric chloride. The ratio of head-to-tail dyads to head-to-head dyads is 4:1. The extent of jr-conjugation in the polymers, as determined by UV-vis spectroscopy, is relatively independent of whether the polymers are in solution or in the solid state. Polymer films of the sodium salt and sulfonic acid forms are amorphous in contrast to non-sulfonated analogs, i.e., the poly(3-alkylthiophenes), which self-organize into semicrystalline solids. Morphological differences between alkane and alkanesulfonate derivatives of polythiophenes are explained on the basis of ion aggregation which prevents polymer chains from achieving the coplanar conformation required for crystallization. Remarkably, the acid form of the polymers, termed "self-doped", exhibit electronic conductivities in the range 5 x 10~2-10_1 S/cm even though they too are amorphous and devoid of long range order. The photochemistry of P3TAS's, in both their sodium salt and "self-doped" form, was investigated. The primary photochemical process is photosensitization and reaction of singlet oxygen, which leads to photobleaching. In oxygenated solutions, P3TAS's are much more photostable than their non-sulfonated analogs due to quenching of photosensitized singlet oxygen by water. Films of P3TAS's take up atmospheric moisture in ambient air and, as a result, exhibit enhanced photostability compared to their non-sulfonated analogs exposed to ambient conditions. Anhydrous films, however, exhibit rates of photobleaching which are comparable to the poly(3-alkylthiophenes). The acid form of the polymers is found to be more photostable than their corresponding sodium salts. Unlike their non-sulfonated analogs, irradiated films of P3TAS's exposed to ambient atmosphere do not cross-link to form insoluble polymer upon irradiation due to the presence of residual moisture. However, photolithography can be performed on polymer films oxidized with ferric chloride. Anhydrous films of P3TAS's are rendered insoluble upon exposure to UV or visible irradiation, thus affording the deposition of negative polymer images.