Microstructure in organic semiconductor thin films has been regarded as the key factor determining the performance of the organic electronics. In case of organic field effect transistors (OFETs) and organic photovoltaics (OPVs), the control of the surface characteristics of the underlying substrates can govern the mesoscale and/or nanoscale ordering of the semiconductor assembled on them. Here, we present various approaches for controlling the highly-oriented growth of organic semiconductors on the gate dielectrics and electrodes to achieve high performance OFETs and OPVs.