Substituted cyclooctatetraenes are a class of interesting and important compounds both theoretically and synthetically. Since Reppe first discovered the Ni-catalyzed tetramerization of ethyne affording cyclooctatetraene in 1948, transition metal mediated synthesis of this type of compounds has become a primary methodology. In this Feature Article, based on our own recent results and other groups' related reports, we describe major achievements on transition metal mediated or catalyzed synthetic methods for substituted cyclooctatetraenes, with focus on reaction patterns, mechanisms, and structural diversity of products.