A new method to prepare reduced graphene oxide (RGO) films was reported. In this method, RGO thin films can be prepared for large areas with controllable thickness and high temperature (>500 °C) is not required. The applications of RGO thin films as electrodes of organic field-effect transistors (OFETs) were investigated by bottom-contact p- and n-channel OFETs using copper phthalocyanine and copper hexadecafluorophthalocyanine as semiconductors. Transistor characterization showed the RGO electrode devices displayed higher mobilities than similar OFETs with Au electrodes, suggesting RGO is a good candidate for OFET electrodes.