 Once the stuff of science fiction, the ability to wire our bodies directly to electronic devices is now a reality. Artificial pacemakers, cochlear implants and deep brain stimulators have all had an extraordinary impact on the quality of life of thousands of people. And as scientists seek new ways to improve how these devices communicate with our bodies, a class of materials known as conjugated polymers is currently leading the way. One of the main problems researchers must overcome in designing bioelectronic implants is properly interfacing rigid electronic devices with the soft tissue in our bodies. In terms of device performance, the problem is essentially one of poor communication. Solid electronic devices communicate through current by shuttling electrons across metallic lines to signal or generate a response. Living tissue, on the other hand, communicates through ion movement by sending and receiving larger charge-laden molecules across the aqueous channels that course throughout the body. Conjugated polymers can effectively bridge this gap because they speak both languages. They conduct both electrons and ions. That's because, unlike more familiar polymers such as polyethylene, polyester or nylon, conjugated polymers have alternating single and double bonds along their molecular backbone. This structure allows electrons to move freely across the links in the polymer chain. And when immersed in an aqueous environment, this electron flow is compensated by the flow of ions. But conjugated polymers still retain their counterparts' ability to be formed into complex shapes and patterns, which is crucial for making electronic implants compatible with biological tissue. This unique combination of properties is derived directly from the molecular level design of conjugated polymers. For example, the minimeric units that are electrochemically chained together to form polyethylene dioxythiophene, or PDOT, show both high chemical stability and strong electrical conductivity. In addition, the simple structure of these units provides a versatile template that can be used to tailor polymers to specific biomedical applications. By attaching different molecules to each unit, for instance, or by growing a polymer with alternating blocks of PDOT and a different polymer, researchers can create implant materials that are more or less hydrophobic, or that cells might find sticky, helping them to grow and mature. In fact, the entire literature on PDOT reads like a rich catalog of designer materials that can help the body accommodate electronic implants. PDOT can be grown into masses of nanofibals that can be easily deformed but still retain high conductivity, or into more regular, mechanically robust microstructures. It can even be grown while embedded in another implant material. Like seeds planted in a flower pot, PDOT precursors can sprout into fibres within a hydrogel, vining upward until they reach the surface. This creates a conductive channel that provides a gentler transition from soft brain tissue to electronic hardware. The development of chemically stable and electrically active conjugated polymers has enabled material scientists and engineers to devise creative new ways to interface bionic devices with living tissue. Continued progress in this multidisciplinary field will require researchers to improve the understanding of how these materials behave over extended periods and how they transport charge in the biological environment.