In recent years, global warming and climate change arising from CO2 emissions have led to significant concerns. Solar energy is among the most abundant renewable energy sources in the world. Despite the abundance of sunlight radiation, effective saving and conversion of this source have caused some challenges. Solar Thermal Fuels (STF) are materials that can absorb the energy of sunlight, changing their structure or conformation upon sunlight absorption, store absorbed solar energy in their molecules and release solar energy as heat at night. Azobenzene molecules are considered as suitable STF molecules. In the present research, a new method for the functionalization of Multiwall carbon nanotube (MWCNT) with Azobenzene molecules to increase the energy stored per Azobenzene molecule was done. Furthermore, the dispersion of Azobenzene modified with MWCNT in polymeric substrates (Ethylene-vinyl acetate) to fabricate a new applied product was done. This polymeric solar thermal fuel composites can be used as films, sheets, fibers and paint to store the energy of sunlight in the day and release this energy as heat at night. The DSC analysis test, FTIR test was indicated the functionalization of Azobenzene molecules with MWCNT. Moreover, the FESEM test, RMS test, and accumulative thermal test were shown the dispersion and thermal conductivity in polymeric solar thermal fuel nanocomposite. This nanocomposite is a likely candidate for the future of solar energy storage materials.