We performed DFT calculations to predict the activation free energies (ΔG ‡ ) of (1-4-Z). We computed the structures and energies of the Z-isomer, E-isomer, and transition structure for each reaction. First, the transition structures were optimized using the EZ-TS code recently reported by our group. After locating the lowest energy transition states, we ran intrinsic reaction coordinate (IRC) calculations and optimized the reactive conformers corresponding to the reactant (Z-isomer) and product (E-isomer) for each thermal Z → E isomerization. All calculations were performed using the Gaussian 16 software. The PBE0 61 /6-31+G(d,p) model chemistry was used for all geometry optimizations and frequency calculations. Vertical excitation energies were calculated using (TD-DFT) with the ωB97X-D 64 /6-31+G(d,p) model chemistry in IEFPCM water .