One of the key drawbacks of previously reported BCB [2π+2σ] cycloaddition reactions is the limited generality with respect to the alkene coupling partner and so we next turned our attention to other classes of olefin which could be employed. In addition to vinyl naphthalene (5y), heterocycles containing Lewis basic atoms such as vinyl thiophene (5z) and thiazole (5aa) were amenable to the cycloaddition reaction, although vinyl pyridine was deemed unsuitable (5ab). Interestingly, this transformation could also be used to facilitate the dearomatisation of heterocycles such as benzofuran (5ac) and indole (5ad), as well as being compatible with enynes (5ae-af), dienes (5ag), enol ethers (5ah) and enamine-type substrates (5ai). These results demonstrate the remarkable variety of olefins that can interact with BCB radical cations and highlight the inimitable reactivity of this synthetic intermediate.