Ionization of azines (s-triazine, pyridazine, pyrimidine, pyrazine, and pyridine) with He*(2(3)S) metastable atoms was studied by (collision-energy/electron-energy-resolved) two-dimensional Penning ionization electron spectroscopy. Collision energy dependence of the partial ionization cross sections (CEDPICS), which reflects interaction potential energy between the molecule and He*(2(3)S), showed anisotropic interaction around the molecules. Assignments of the Penning ionization electron spectra and ultraviolet photoelectron spectra were discussed on the basis of different behavior (positive or negative slope) of CEDPICS. Theoretically computed CEDPICS of s-triazine by classical trajectory calculations were found to be useful to confirm the assignment of the ionic states.