The rapid expansion of the Internet of Things (IoT) has fueled the exploration of novel materials and device architectures to meet the demands of applications such as smart wearables, environmental sensors, and flexible displays. In this context, graphene has emerged as a remarkable candidate due to its exceptional electronic and mechanical properties that are suitable for the development of flexible electronic devices. This work investigates the potential of C60- and Pentacene-doped Graphene Field Effect Transistors (GFETs) as building blocks for complementary inverters in digital and/or analog flexible electronic circuits. The fabricated complementary inverters use doped graphene as the channel material for both the n- and the p-type transistors. The channel length of the GFETs spans the range from 5 μm to 100 μm and does not affect the measured transfer characteristic of the inverters, which is obtained by operating the transistors between their respective Dirac points. While the GFET-based inverters show a voltage gain of about 2×10−2 and a bandwidth up to 10 kHz, circuit simulations indicate that by integrating the GFETs and by carefully designing the chip metal interconnects, the inverter could reach operating frequencies in the GHz regime. Additionally, scaling the graphene channel length allows to tune the cutoff frequency and static power dissipation of the inverter, potentially meeting the requirements of specific applications.