We performed additional DFT studies to shed more light on this matter by finding answers to the following questions: (1) Why does thermal ring-opening of dihydro-4H-cyclobuta [c]isochromenes lead to the anti-Woodward-Hoffmann products?; (2) Why is the thermal ring-opening of dihydro-4H-cyclobuta [c]isochromenes to 1H-2-benzo [c]oxocins associated with dihydronaphthalene formation?; (3) Why is thermal switching possible with an aryl substituent at the 4-membered ring, but not with alkyl substituents at this position?