In this paper, density functional theory (DFT) with asymptotically corrected potentials is used to investigate CH3CN, CH3NC, CH3SCN, and CH3NCS molecules. For the energies of sigma* and pi* temporary anion states, the stabilized Koopmans' theorem (S-KT) using long-range correction functional and stabilized Koopmans-based (S-KB) approximation using local functional, are adopted. The stabilization procedure is accomplished by varying the exponents of appropriate diffuse functions. Results indicate that the calculations based on asymptotically corrected density functionals can yield better energy results of temporary anion states over conventional DFT methods.