Organic mixed ion-electron conductors are renowned for their unique ability to efficiently conduct both electrons and ions, finding applications across various fields such as electronics and bioelectronics. In this colloquium, I will delve into the fundamentals of ionic-electronic transport in organic mixed conductors and showcase their applications in electrochemical transistors, biosensors, and low-voltage artificial synapse memory systems, which emulate the function of neurons (also known as neuromorphic devices).