In this study, we developed intrinsically thermo-responsive and conductive polymers (TR-CPs) with a fully reversible sol-gel transition to circumvent the need for covalent and irreversible crosslinking in conductive hydrogels. We leveraged the self-assembly of block polyelectrolyte complexes to achieve stable and well-defined colloids. Above the transition temperature (35-36 °C), dispersions of the TR-CP undergo a very rapid (< 1 min) and isovolumetric gelation under a range of pH and ionic environments, resulting from the aggregation of the colloids into a bicontinuous network. These gels are electrically conductive and cytocompatible, and therefore amenable to applications in bioelectronics, which we demonstrated in a conformal and reusable surface electromyography device.