Solar energy storage and conversion have remained significant global challenges. This article discusses how to fabricate a polymeric solar thermal fuel (P‐STF) composite with unique thermal storage abilities. In this regard, we aim at developing a novel method for dispersing multi‐walled carbon nanotubes (MWCNTs) functionalized with azobenzene molecules (modified azobenzene molecules) in ethylene‐vinyl acetate (EVA). The modification of azobenzene (functionalization) enhances the energy storage density of AZO molecules, and the addition of fillers (MWCNT) leads to the production of the P‐STF composite with the potential to store and convert solar energy to thermal energy. The differential scanning calorimetry (DSC) test verifies the P‐STF composite's capacity to absorb solar energy and release it as heat. Thus, the uncharged nanocomposites required heat energy at the melting point temperature of EVA (Enthalpy 18.392 J/g). However, the EVA‐AZO‐MWCNT 10% and EVA‐AZO‐MWCNT 5% nanocomposites released heat energy rather than requiring it to melt with enthalpy −37.6526 and −1.2609 J/g, respectively, which indicates the heat release in the P‐STF composite. Moreover, oscillatory shear rheological measurement (RMS) and field emission scanning electron microscopy (FESEM) demonstrate that modified azobenzene (MWCNT‐AZO) is well dispersed in the polymer matrix (EVA).