The synthesis of poly(3-hexylthiophene) by the oxidative coupling of thiophene monomer with anhydrous ferric chloride in organic solvent was investigated. Various experimental factors in the polymerization reactions to yield poly(3-hexylthiophene) including reaction temperatures, the mole ratios of 3-hexylthiophene and ferric chloride, types of solvent and additives, with the goal of obtaining higher %yield and Head-to-Tail ratio (%HT), The best synthesis condition of poly(3-hexylthiophene) was obtained when running the reaction at room temperature in dichloromethane and at the mole ratio of 3-hexylthiophene monomer : ferric chloride = 1:3. Under this condition, the polymer was obtained in 94% yield with 78% HT. Various doping methods of poly(3-hexylthiophene) were investigated. For protonic acid doping, trichloroacetic acid and trifluroacetic acid were found to successfully give the doped products without precipitation while all Lewis acid dopings resulted in precipitation of the doped products. Solvato-controlled doping with the combinations of either methanesulfonic acid –thiophene, ferric chloride –pyridine, or aluminium chloride –pyriding gave the doped polymer films without pre-precipitation problem.