We report the synthesis, morphology, and the field effect transistor (FET) characteristics of the crystalline diblock copolymers of poly(3-hexylthiophene) and syndiotactic polypropylene (P3HT-b-sPP). Four diblock copolymers with various sPP block lengths, P3HT 16K -b-sPP 3K (P1), P3HT 16K -b-sPP 6K (P2), P3HT 16K -b-sPP 9K (P3), and P3HT 16K -b-sPP 14K (P4), were prepared by the click coupling of N 3 -capped sPP and ethynyl-capped P3HT. The stereoregular crystalline block sPP developed different types of molecular stacking structures and led the P3HT domains to pack lamellar edge-on structure with improved charge transporting characteristics, as evidenced by the grazing incidence wideangle X-ray scattering (GIWAXS), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The FET hole mobilities of P1−P3 thin films were 4.15 × 10 −3 , 4.16 × 10 −2 , and 3.95 × 10 −3 cm 2 V −1 s −1 , respectively, which were up to 1 order of magnitude higher than that of the parent P3HT thin film (1.43 × 10 −3 cm 2 V −1 s −1 ). The crystalline-stereoregular crystalline diblock P3HT-b-sPP demonstrates that using the lattice matching concept could well clarify the molecular stacking structure of conjugated polymer segments in order to further improve the performance of organic electron devices.