comprises materials and devices that can fulfill just this dual ionic-electronic capability. Iontronics utilize the coupling of electrical and ionic signals in conducing polymers, leading to, for example, organic electrochemical transistors (OECTs), [2] electrolyte-gated (also known as electric doublelayer capacitor-gated) organic field-effect transistors (EGOFETs), [3,4] organic electrochemical biosensors, [5,6] and iontronic delivery electrodes and devices. [7][8][9][10][11] In iontronic delivery devices (Figure 1), chemical gradients are created by controlled release of charged biomolecules (ions) at specific locations at specific times. [7,8,12] Ions are transported to these release sites through ionic conductors due to applied electric fields between electrodes. The ionic conductors form the foundation of iontronic resistors (organic electronic ion pumps, OEIPs), diodes, and transistors which can be combined into circuits for, for example, multiplexing, addressing, and signal processing. These iontronic circuits behave analogous to traditional electronics, but use ions as charge carriers rather than electrons, and allow for the development of fully chemical systems generating complex signal patterns at high spatiotemporal resolution and biochemical specificity.There are several other techniques for electronic control of substance release, drug delivery, or ion transport related to this form of iontronics. These include techniques such as microfluidic and microelectromechanical systems (MEMS) based micropumps, [13] iontophoresis, [14,15] and organic electronic redox-mediated controlled release. [11,16] In comparison to these technologies, iontronic drug delivery provides a means of simultaneously achieving high delivery precision, minimal (or zero) liquid transport that could interfere with fragile biochemical microenvironments, continuous resupply of the transported substance, and (in principle) exact control over delivered amounts, even at speeds on par with synaptic signaling. In addition, as they are based on well-established solid-state device manufacturing techniques, iontronic components and systems can be miniaturized, addressed, and integrated with complex electronic systems in a straightforward manner. These features of iontronics combine to enable the lowest dose possible. With other techniques for substance release and transport, larger doses are often distributed (usually in solution phase) with less control, which could result in unwanted side effects. Other technologies have their advantages primarily in potentially simpler device design, the ability to transport larger molecules (e.g., In contrast to electronic systems, biology rarely uses electrons as the signal to regulate functions, but rather ions and molecules of varying size. Due to the unique combination of both electronic and ionic/molecular conductivity in conjugated polymers and polyelectrolytes, these materials have emerged as an excellent tool for translating signals between these two realms, hence the field of organic bioelectroni...