The cyclic structure theory of benzene is the highest achievement of classical structure theory. On May 1890, 1 1, on the 25th anniversary of the birth of the structural theory of benzene, the London Chemical Society pointed out: "As a clever concept of closed chain structure, benzene's influence on the development of chemical theory, its motivation to study the inherent problems of isomerization in derivatives of similar compounds, and its pioneering role in large-scale industries such as coal tar dyes.