Soft electronic systems based on polymers and composites are expected to have important applications that range from conformable biomedical devices to mechanically robust and portable systems for energy conversion and storage. The fundamental challenge of the field is the co-engineering of softness, responsiveness, and electrical properties in a single material or system of materials. This symposium will highlight several successful and nascent approaches to this challenge. These approaches include nanostructured composites (e.g., semiconducting or conducting particles dispersed in a polymeric matrix), deterministic composites (i.e., those based on patterned films on elastomeric substrates), and intrinsically stretchable organic conductors and semiconductors (i.e., conjugated polymers whose molecular structure or solid microstructure permits substantial deformation). The topics of this symposium will span the synthesis, fabrication, characterization, modeling, and application of this class of soft and functional polymers and composites. This symposium will provide a forum for a discussion of the fundamental aspects of the chemistry of materials, the physics of solids and soft matter, and the fabrication of devices for highly impactful technologies. The anticipated scope of these technologies will be very broad, which may range from healthcare to clean energy.