Itoh and colleagues investigated the thermal racemization of chiral isomers and photoexcited planarization of divergent-shape COT derivative (COTh) in a twodimensional design . The kinetics of ring flipping determined the energetic impact of COTh's excited-state aromaticity. In this study, Baird's rule served as the core molecular vibration mechanism, which began research in 1972 defining the configuration flipping and photophysical properties of anti-aromatic or anti-Hückel rules for cycloalkynes with 4nπ electrons in the ground state. Non-planar conformations with alternating bond lengths reduce unfavorable conjugated electronic structures. However, 4n cycloalkynes are inclined to adopt planar conformations under photoexcitation, which stabilizes their excited-state energy and leads to planar aromatic conjugation.