Conductive materials that can conform to the human body and exhibit stable electrical output under strain is of great importance to the field of wearable electronics, particularly for applications in biomedical research. The desired material needs to have good electrical conductivity, stretchability, compliant stiffness, high toughness, and preferably can self-heal upon damage. 3D printing technologies serve as the bridge between such new materials and personalized electronic devices that can be tailor fit to the body and organ contour of each individual. In this talk, I will discuss the design and synthesis of a viscoelastic and self-healing conjugated polymer that are 3D-printable. The viscoelasticity of the polymer can be tuned by modifying the chemical structure and molecular weight of the dopant polymer. Room temperature self-healing capability is created by incorporating reversible bonding moieties into both the conjugated polymer and its dopant polymer. Concentrated solutions of this polymer undergo significant shear-thinning, allowing the material to be extruded via a pressurized nozzle with 3D movement control. The printed objects are elastic and exhibit good conductivity, which can be further enhanced with the addition of Ag nanowire fillers.