In this research at the first Promethazine drug and its fullerene derivative were optimized. NMR calculations for the complexes were carried out at the B3LYP/6-31G*quantum chemistry level. Promethazine is not used as an antihistaminic drug for anyone. In the pharmaceutical composition of promethazine (RS) - N, N-dimethyl-1- (10H-Phenothaiazin-10 yl) -propen-2-amino, two aromatic rings In this study, halogens are connected to one of their loops and the changes in the type of halogen at the surface * HF / 6-31G are calculated. The calculations show that, by changing the type of halogen based on the variation of electronegativity of halogens, the aromatase level is as follows increase. R-F> R-Cl> R-Br. The data in tables and graphs and shapes were compared and discussed.