Fossil fuels, which represent an important villain for the terrestrial ecosystem, are non-renewable sources of energy, which prompt many discussions about how long petroleum will remain available for use. As an alternative, new energy sources have been explored, including biofuels, such as biodiesel and ethanol. However, their use can raise some problems, such as lower storage stability associated with poor oxidation stability and lower energy availability, which affect consumption, emissions, and energy efficiency. In this context, a comprehensive study with structural description, theoretical calculations, and calorific power test was performed for a new halogen chalcone 4-(4-chlorophenyl)-1[4-(2-oxo-2-phenylethoxy)phenyl]butan-2-one to understand its supramolecular arrangement and physicochemical properties. The structural description was carried out by X-ray diffraction with the contribution of Hirshfeld surfaces. The theoretical calculations were carried out using density functional theory with the contribution of calorific power determined by a calorimetric pump. All observed results characterize the new chalcone as a potential additive for biofuels.