ABC-type asymmetric star polymers containing a P3HT segment were successfully synthesized by polymer coupling/linking reactions by combining the Kumada catalyst-transfer polymerization and living anionic polymerization for the first time. The synthetic methodology involves the following three stage reactions: (a) the anionic linking reaction between ?-chain-end-functionalized P3HT with a bromobutyl moiety (P3HT-C-4-Br) and living anionic PS end-capped with 1-(3-tert-butyldimethylsilyloxymethylphenyl)-1-phenylethylene (1), (b) the transformation reaction of the 3-tert-butyldimethylsilyloxymethylphenyl (TBDMS) moiety at the junction between the P3HT and PS segments into the a-phenyl acrylate (PA) moiety through the hydroxymethylphenyl moiety, and (c) the anionic linking reaction between PA-in-chain-functionalized P3HT-b-PS and living anionic P2VP. Indeed, the well-defined ABC star polymers in which A, B and C are poly(3-hexylthiophene) (P3HT), polystyrene (PS), and poly(2-vinylpyridine) (P2VP), respectively, could be synthesized. The molecular weights and compositions of the star polymers were controllable by possessing extremely low D values (D < 1.05). Two distinct transition temperatures (T-g,(PS+P2VP) and T-m,(P3HT)) were clearly observed in the DSC thermograms of the ABC star polymers, indicating the phase separation between the (PS+P2VP) and P3HT domains. The vibronic absorption of the ABC star polymer films based on the UVvis spectroscopy indicated a high degree of ordering of the P3HT crystalline structures, supporting the isolation of the P3HT domains although the PS and P2VP segments are connected to P3HT at the core. In the AFM phase images of the ABC star polymer thin film surface, continuous fibril structures were clearly seen. GISAXS experiments confirmed the orientation of the fibril structures with the mean period distances depending on the P2VP arm lengths. The GIWAXS results showed that the P3HT crystalline domains in the microphase-separated P3HT domains align with an edge-on rich orientation and the pi-pi stacking distance in the range of 0.380-0.393 nm also depending on the length of P2VP segments.