In this study, the charging energies of both modified and pure thiol-ended thiophene molecule were calculated with the quantum-chemical methods. The geometry optimizations of the molecules in gas phase have been performed for different charge states (+1, 0, -1) of the different boron impurity orientations at DFT level. The adiabatic ionization energy and adiabatic electron affinity of the thiol-ended thiophene molecule with four boron impurity derivatives were calculated using B3LYP/6-31G(d,p)++ basis set. The influence of the boron impurity has been investigated to control and adjust the HOMO-LUMO gap of the molecules. The calculated addition energies were compared and some of characteristic ones were depicted with the electrostatic maps. The molecule which has geminal boron atoms onto the sulphur has the largest addition energy and a larger HOMO-LUMO gap than the other thiol-ended thiophene molecule derivatives. This molecule with the largest addition energy in comparison with the others is the most possible candidate for MSET application with a good performance. As a consequence, both increased and decreased addition energies were obtained due to the number and orientation of the boron impurities in the thiol-ended thiophene molecule.