The double hybrid B2PLYP-D3 functional with the Dunning's correlation consistent basis set (triple zeta), i.e. cc-pVTZ, was used to obtain the equilibrium geometries, frequencies, and zero point energies (ZPE) of the neutral molecules and corresponding cations of benzonitrile and o/m/pcyanotoluene. Single point energies (SPE) were computed at the level of CCSD(T)/aug-cc-pVTZ. The scale factor of 0.983 for ZPE correction is adopted.