Graphical Abstract: 5,6-Dichloro/dimethyl-2-(2´,3´/2´,4´/2´,5´/3´,4´/3´,5´-dimethoxyphenyl)-1H-benzimidazoles were synthesized and characterized experimentally and theoretically. The optimized molecular geometry, zero point energy, dipole moment, ESE and charge distributions were calculated by Gaussian 09 using DFT method. The calculated energy values with ZPE correction and DFT show that the methyl derivatives are more stable than the chloro forms.