In this report, we investigate a formation mechanism for polymer chains aligned with various semiconductor polymers and a microstructure for directionally aligned film through systematic analysis that includes polarized UV–visible–near infrared (UV–vis–NIR) absorption spectroscopy, atomic force microscopy, polarized charge modulation microscopy (p-CMM), and incident X-ray diffraction (GIXD) measurements. Through this study, we make two important observations: first, the highly aligned organic polymer semiconductor films are achieved by off-center spin coating of the preaggregated conjugated polymer solution. Second, the directionally aligned conjugated polymer films exhibit a larger anisotropy on the top surface compared with bulk film, which allows effective mobility improvement in top-gate/bottom-contact field-effect transistors with high performance uniformity. Finally, we demonstrate high-mobility …