Although the Mülliken population do not supply a exact number of charge transfer, but indicates the trend and correct order of the charge transfer process. Also by analyzing the Mülliken population, we have found the calculated total magnetic moment for theFeCl3molecule adsorbed in BNNT, the total magnetic moment is4.92µB, which is very near to the total magnetic moment of isolated molecule, 5.00µB, so we infer that the magnetization of the system is due exclusively to the molecule. In the others systems studied, we observed that the system formed with FeCl3molecule inside the BN nanotube is not stable, while CrO3molecule inner BNNT shows stable with the binding energy of −1.50 eV. The systems with FeCl3and CrO3molecules interacting with BN nanotube formed the Cl N,Cl B, O N and O B bonds that are not energetically favorable as can be seen through binding energy value (Table 1) and our calculation shows that FeCl3(CrO3) molecule formed bond Cl N(O N)and Cl B(O B) that have the same final configurations. Although this system not stable, occurs charge transfer and a great decrease in the energy gap (see Table 1).