Fast ambipolar CMOS-like logic is demonstrated using a new selenophene-based donor-acceptor polymer semiconductor. The polymer exhibits saturation hole and electron mobilities of 0.46 cm2/Vs and 0.84 cm2/Vs. Inverters are fabricated with high gains while three-stage ring oscillators show stable oscillation with an unprecedented maximum frequency of 182 kHz at a relatively low supply voltage of 50 V.