A process composed of subjecting a reaction mixture comprising a reaction medium, a coupling agent, and a precursor to a coupling temperature to preferentially form a desired small molecular thiophene compound in a single-step synthesis, wherein the precursor consists of: (i) an optional divalent linkage, and (ii) a plurality of thiophene units, each thiophene unit being represented by structure (A) ##STR00001## wherein each thiophene unit is bonded at either or both of the second ring position and the fifth ring position.