In this work, we realize complementary circuits with organic p-type and n-type transistor integrated on polyethylene naphthalate (PEN) foil. We employ evaporated p-type and n-type organic semiconductors spaced side by side in bottom-contact bottom-gate coplanar structures with channel lengths of 5 μm. The area density is 0.08 mm2 per complementary logic gate. Both p-type and n-type transistors show mobilities >0.1 cm2/V s with Von close to zero volt. Small circuits like inverters and 19-stage ring oscillators (RO) are fabricated to study the static and the dynamic performance of the logic inverter gate. The circuits operate at Vdd as low as 2.5 V and the inverter stage delay at Vdd = 10 V is as low as 2 μs. Finally, an 8 bit organic complementary transponder chip with data rate up to 2.7 k bits/s is fabricated on foil by successfully integrating 358 transistors.