Alkyl-substituted thiophene-2,3-dithiolate ligands are prepared through a Thio-Claisen rearrangement of 4,5-bis(propargylthio)-1,3-dithiole-2-thione derivatives'. The two novel dithiolate ligands, namely, 4,5-dimethyl-thiophene-2,3-dithiolate (alpha-Me(2)tpdt) and 4-ethyl-5-methyl-thiophene-2,3-dithiolate (alpha-EtMetpdt), are engaged in anionic Au(III) square planar complexes formulated as [Au(alpha-Me(2)tpdt)(2)](-) and [Au(alpha-EtMetpdt)(2)](-), isolated as Ph4P+ salts. Monoelectronic oxidation gives the neutral radical complexes [Au(alpha-Me(2)tpdt)(2)](center dot) and [Au(alpha-EtMetpdt)(2)](center dot). The latter crystallizes into uniform stacks with limited interstack interactions, giving rise to a calculated half-filled band structure. It exhibits a semiconducting behavior with room temperature conductivity of 3 x 10(-3) S cm(-1), indicating that this single-component conductor can be described as a Mott insulator. The different structures observed in [Au(alpha-EtMetpdt)(2)](center dot) and the known [Au(Et-thiazdt)(2)](center dot) complex (Et-thiazdt: N-ethyl-thiazoline-2-thione-4,5-dithiolate), despite their very similar shapes, are tentatively attributed to differences in the electronic structures of the ligand skeleton.