The processes of the formation of J-aggregates during the dissolution 2,2-difluoro-4,6-di(4'-methylphenyl)-1,3,2-dioxaborine crystals (1) and their subsequent dissociation have been studied by absorption and luminescence spectroscopy and quantum-chemical modeling. It is shown that two luminescent centers are observed in the solution 1: monomeric luminescence and luminescence of J-aggregates (dual luminescence). Evolution of absorption, excitation and luminescence spectra is observed over time, indicating a slow dissociation of J-aggregates.