Tissue engineering generally involves the proliferation and differentiation of cells within a scaffold that mimics the native extracellular matrix (ECM). Hydrogels are often used as scaffolds due to their high water content, biocompatibility, and biodegradability.[1, 2] However, they generally have weak mechanical properties and low conductivity, which limit their application in regulating the behavior of electroactive cells, such as skeletal, cardiac, and neural cells.[3] Therefore, controlling the mechanical and electrical properties of hydrogels is desirable in regulating cell behaviors. Electrically conductive and mechanically strong hydrogels have other important applications, such as in real-time monitoring of cellular activities,[4, 5] developing hybrid three-dimensional (3D) electronics-tissue materials,[6, 7] and as bioactuators.[8]