In this study, a new additive substance synthesized by chemical mixing of safflower oil and boric acid in sulfuric acid catalysis in the laboratory environment and the effects of the synthesized additive on the physical and rheological properties of the bitumen were investigated. In this context, modified bitumen samples obtained by adding 0,3%, 0,5%, 0,7% and 1% (bitumen weight) of the synthesized additive substance with 50/70 penetration bituminous. Structural properties of the obtained additive determined by Fourier Transform Infrared Spectroscopy (FT-IR) analysis method, while the morphological structure of pure and modified bitumen determined by Scanning Electron Microscopy (SEM) analysis. In order to determine the physical and rheological properties of the bituminous binder, penetration, softening point, ductility, force ductility, dynamic shear rheometer (DSR), rotational viscometry (RV) and rolling thin film oven test (RTFOT) tests were applied to the pure and modified bitumen samples. As a result of the experiments, it has been observed that the synthesized contribution improves the pure bitumen trace and aging resistance, machinability, tensile performance, elongation properties as well as temperature sensitivity.