One-photon MATI spectra of phenylacetylene and benzonitrile were obtained by using vacuum ultraviolet radiation generated by four-wave difference frequency mixing in Kr. Accurate ionization energies of phenylacetylene and benzonitrile were determined from the positions of the 0-0 bands, which are 8.8195 +/- 0.0006 and 9.7288 +/- 0.0006 eV, respectively. Vibrational frequencies of the molecular ions were determined from the spectra also. Assignments were made by utilizing the symmetry selection rule and frequencies and Franck-Condon factors calculated at the BP86, B3LYP, and B3PW91 density functional theory levels with the 6-311++G(2df,2pd) basis set.