Employment of bulky magnesium amide such as Knochel-Hauser base to the reaction of 2-halo-3-substituted thiophene undergoes deprotonation at the 5-position. Following addition of a nickel(II) catalyst induces polymerization to afford head-to-tail-type highly regioregular polythiophenes in a facile manner. 1. dehydrobrominative polymerization 2. Chlorothiophene is also available!! Combination of RMgX and catalytic R2NH can also be employed instead. 3. Synthesis of poly(thienylene arylene)s　4. Extremely high-molecular-weight polythiophene (Mw: higher then 800 KDa; Photo: Self-standing film of thus obtained polythiophene) 5. Combination of lithium amide and MgX2 (ratio:1-3) wil also be replaced with Knochel-Hauser base 6. Formation of thiophene-Li species: Murahashi coupling polymerization. 7. Cross-coupling polymerization via C-S bond cleavage.