Photochemical dimerization of a fluorinated di­benzyl­ideneacetone in chloro­form solution

(1E,4E)-1,5-Bis(2,6-di­fluoro­phen­yl)penta-1,4-dien-3-one dimerizes under sunlight in chloro­form solution to form the corresponding cyclo­butane derivative. The dimer shows the `truxillic acid'-type arrangement of crystallographic centres of inversion, with cell dimensions closely related to those of the monomer.