The chain configuration in conjugated polymer films has a significant impact on the electronic and optical properties of polymer semiconductors, which in turn dictate the device performances of polymer electronics. This article presents a new method to control chain orientation in polymer semiconductors by direct nanoimprint. Nanoimprint-induced chain orientation in conjugated polymer imparts strong optical birefringence in patterned microstructures. X-ray diffraction on patterned films exhibits higher level of chain ordering as nanoimprint temperature increases. Polarized absorption spectra show progressive redshift at higher nanoimprint temperature. The carrier mobility in thin-film transistors based on nanoimprinted grating equals to 12 times of that without patterning. Anisotropies of material properties and device performance are observed in all conjugated polymer structures and devices patterned by nanoimprint. It is expected that the unique ability to control chain orientation will enable nanoimprint to play an important role in tailoring the performance of polymer electronics and sensors.