The applicability of this long-lived triplet state in [2+2] cycloadditions of various chalcones 1 and coupling partners was evaluated using the established reaction conditions (Scheme 2) on differently substituted substrates. Electron donating or withdrawing groups, as well as halogen substitution of 1 are tolerated. The corresponding cyclobutanes with 1,1-diphenyl ethylene are formed in moderate to good yields with varying isomeric ratios (3b-3i). In contrast to previous reports on triplet state cycloadditions of chalcones, head-to-tail selectivity was not achieved, evident by the formation of 4 isomeric species. Next, replacement of the simple phenyl ring with a more complex benzo[d] [1,3]dioxole was successful (3j). A 2,3-dimethylbutadiene was introduced efficiently, resulting in the corresponding cyclobutane 3k in a yield of 49 %. Simple styrene coupling partners instead of 1,1 -diphenyl ethylene resulted in product mixtures with multiple diastereomers formed in significant quantities. Furthermore, similar Rf values of the dimer of 1a and the cyclobutane products resulted in challenging separations. Nonetheless, electron rich and electron poor styrenes were tolerated (3a, 3l-3n). A more comprehensive list of substrates showing significant reactivity can be found in the SI. Dimerization of 1a only proceeded sluggishly (see SI).