Electronics open the door to a wealth of promising biomedical therapies, from implanted devices that therapeutically stimulate organs, to regenerative medicines that use electrical cues to guide stem cell differentiation towards target lineages. Yet, a severe mismatch in mechanical properties like stiffness and stretchability at the bio-electronic interface remains a major challenge. In this talk, I will focus on materials approaches to address these mechanical mismatches, focusing on intrinsically flexible and stretchable conjugated polymer-based semiconductors and conductors. I discuss the multi-length scale design strategies that have enabled researchers to realize desirable mechanical properties without compromising on high electrical performance.