Shown this study the absorption and fluorescence spectra for organic semiconductor dissolved in a polar solvent. Used a diluted concentration to the purpose of minimizing the phenomenon of self-absorption. The measurements of these solutions spectra showed the electron exchange, which led to the energy transfer from the guest to the organic semiconductor. And shown the presence of energies activation organic semiconductor doping different proportions of 2-Methylnaphthallene; each activation energy has different mechanical connecting which could be interpreted by relying on the bands theory of semiconductor which proposes a transition charge which carriers from the fermi donor to the conduction band in the semiconductor negative (n-type)at high temperatures by thermal excitation. The X–ray diffraction spectra possess one sharp and two small peaks. It means that the film is polycrystalline in nature structure.