After successfully exploring the radical cation-based [4+2] cyclization, we propose the radical cation 10 •+ can also be applied in the radical cation-based [2+2] cyclization We started with anethole and styrene, resulting in a moderate yield with regioselectivity being strictly controlled (13a). Substituting styrene with paramethoxy group led to a decline in yield (13b). When using an electron-deficient ketone, the yield was modest after prolonged irradiation (13c). We found that dimerization is also feasible, 13d was isolated after 48 h irradiation. To inhibit oxidative cleavage of the substrates, we tested degassed solvent, but this only resulted in trace amounts of the product, supporting the proposed role of oxygen in the reaction mechanism. Another dimer 13e was also isolated in a modest yield, which was suppressed by competitive polymerization.