Closed cycle systems offer an opportunity for solar energy harvesting and storage all within the same material. Photon energy is stored within the chemical conformations of molecules and is retrieved by a triggered release in the form of heat. Until now, such solar thermal fuels (STFs) have been largely unavailable in the solid-state, which would enable them to be utilized for a multitude of applications. A polymer STF storage platform is synthe-sized employing STFs in the solid-state. This approach enables uniform fi lms capable of appreciable heat storage of up to 30 Wh kg −1 and that can with-stand temperature of up to 180 °C. For the fi rst time a macroscopic energy release is demonstrated using spatial infrared heat maps with up to a 10 °C temperature change. These fi ndings pave the way for developing highly effi -cient and high energy density STFs for applications in the solid-state.