We report the fabrication of simply structured and high performance organic complementary inverters based on an ambipolar organic semiconductor, 8,9,10,11-tetrachloro-6,13-bis-(triisopropylsilylethynyl)-1-azapentacene (4Cl-Azapen). Individual transistors using symmetric Au electrodes showed high and balanced performance, with good hole (up to 0.23 cm2V−1s−1) and electron (up to 0.21 cm2V−1s−1) mobilities. Integrated complementary inverters showed sharp inversions with high gains (>180) and negligible hysteresis. The inverters using low-cost electrodes, Ag and Cu, also exhibited high gains and high noise margins (>75% of the ideal value).