The synthesis of poly(3,3 "- and 3’,4’-dialkyl-2,2’:5’,2 "-terthiophene)s possessing a full ordered regiochemistry of bonding and substitution, as well as a conjugated chain with the minimum possible amount of steric interactions between the substituents, is described. The synthesis was achieved through the simplest chemical method, namely the oxidative polymerization reaction based on FeCl3 as oxidant. The structural regularities of the polymers have been confirmed by Fourier transform infra-red (FT i.r.) and H-1 nuclear magnetic resonance (n.m.r.) spectroscopy. Experimental conditions of special interest for improving the yields and molecular weights of the neutral soluble polymers are discussed.