We report on a convenient and simple process to prepare highly regioregular poly(thiophene)-based multiblock copolymers by a novel thermally induced coupling reaction. Diblock copolymers of 3-hexylthiophene (3HT) and 2,5-dibromo-3-(2-(2-tetrahydropyranyl-2-oxy)ethyl)thiophene (THPET) end-capped by a nickel complex (Br-P3HT-b-PTHPET-Ni(dppp)Br) are first prepared using Ni(dppp)Cl-2 as catalyst at 30 degrees C by Grignard metathesis polymerization (GRIM process). The coupling of these alpha-bromo, omega-Ni(dppp)Br telechelic diblock copolymers then occurs by heating the solution of the copolymer at 80 degrees C for a few hours without adding any additional reagent. Reactions are complete in only 10 min when heating the copolymer at 120 degrees C using microwaves. The deprotection of the alcohol groups of PTHPET blocks allows further modifications such as the incorporation of acrylates by esterification. AFM analysis on thin films shows the influence of the nature of side chains (protected alcohol or acrylate), the molecular weight, and the architecture (diblock or multiblock) of the copolymer on the supramolecular organization of the polythiophene chains.