The photochemical [2+2]-cycloaddition between alkenes proved to be a powerful strategy to construct cyclobutanes. In this context, we wondered if diene 1 (easily obtained from the commercially available starting materials, please see next paragraph) would undergo an intramolecular cyclization into the needed 2-oxabicyclo [2.1.1]hexane core. Direct irradiation of diene 1 in acetonitrile under different wavelengths gave only traces of products (entries 1-4, Table ). Irradiation with a Hanovia broad wavelength mercury lamp gave the needed product along with many side products (entry 5). Next, we tried the addition of available organic ketones for the triplet sensitization of the styrene moiety. Indeed, smooth formation of the needed products 1a was already observed. The best result was obtained with benzophenone (entry 7), whereas acetophenone and substituted benzophenones also worked, but provided the product with lower yields (entries 6, 8, 9). Among all tested solvents (entries 10-13), the best outcome was obtained in acetonitrile. Without irradiation, the reaction did not take took place neither at room temperature nor under heating (entries 14, 15).