A new pyridine-substituted dithiolene complex, PPh4[Au(4-pdddt)2] (3), was prepared and characterised. Cyclic voltammetry shows three redox processes corresponding to the interconversion between dianionic, monoanionic, neutral and cationic states, as often presented by this type of bis(dithiolene) complexes. However, the last oxidation process in this compound leads to a polymerised species obtained as an electrodeposited film. By potentiostatic electrodeposition, thin films of either the neutral gold complex, [Au(4-pdddt)2] (4), or the polymerised cationic species can be obtained. Both films absorb strongly in the NIR region and have properties consistent with the incorporation of the intact metal bis(dithiolene) complex. A mechanism for polymerisation through formation of S–S interligand bonds is proposed.