fitting their new experiments on some aromatic hydrocarbons . The photoionization cross-sections rises smoothly in the FC region since the geometric configuration of the ionization state and the neutral state does Figure shows the measured and calculated photoionization crosssections of o/m/p-cyanotoluene. In the supplement, we provide enlarged cross sections at about 2.5 eV after the threshold to give more detailed features (see Figure ). Similar to that of benzonitrile, the FC region involves the contribution from the HOMO-1 orbital for each cyanotoluene isomer. A plateau region exists about 1.5 eV behind the FC region, and then the cross-sections continues to increase. When the photon energy rises to about 3 eV higher than the threshold, the cyanotoluene cations tend to dissociate. Considering the dissociation dynamics at high energies, we only include the contribution of deep orbitals with ionization energies lower than the dissociation energy, i.e. HOMO-1 to HOMO-4 for o-and m- cyanotoluene, HOMO-1 to HOMO-3 for the para-isomer. The fragments signal of C7H6 and C8H6N are also shown in Figure . The o-cyanotoluene and p-cyanotoluene show characteristics similar to shape resonance at about 12.3 eV. The shape resonance is caused by the temporary trapping of photoelectrons with high angular momentum by the centrifugal barrier in the electron-ion potential, the shape resonance has a great influence on the cross-sections, final state branching ratio, and photoelectron angular distribution. Due to the high l characteristic of virtual orbitals, the photoionization absorption cross-sections of linear internal alkynes show obvious shape resonance characteristics. The shape resonance characteristics near the threshold photoionization of p -cyanotoluene indicates a similar effect of the carbon -nitrogen triple bond as the carboncarbon triple bond. The related mechanism needs to be further studied. In