Organic electrochemical transistor (OECT)–based inverter introduces new prospects for energy-efficient brain-inspired artificial intelligence devices. Here, we report single-component OECT-based inverters by incorporating ambipolar p(gDPP-V). Notably, p(gDPP-V) shows state-of-the-art ambipolar OECT performances in both conventional (p/n-type mode transconductance of 29/25 S cm −1 ) and vertical (transconductance of 297.2/292.4 μS μm −2 under p/n operation) device architectures. Especially, the resulting highly stable vertical OECT–based inverter shows a high voltage gain of 105 V V −1 under a low driving voltage of 0.8 V. The inverter exhibits undiscovered voltage-regulated dual mode: volatile receptor and nonvolatile synapse. Moreover, applications of physiology signal recording and demonstrations of NAND/NOR logic circuits are investigated within the volatile feature, while neuromorphic simulations with a convolutional neural network and image memorizing capabilities are explored under the nonvolatile behavior. The ambipolar OECT–based inverter, capable of both volatile and nonvolatile operations, provides possibilities for the applications of reconfigurable complementary logic circuits in novel neuromorphic computing paradigms.