3-Methyl-4,6-diphenylfuro[3,4-d]isoxazole -A New Heterocyclic SystemMetal-catalyzed nitrogen extrusion from the diazo compound 8 yields 3-methyl-4,6-diphenylfuro[3,4-d]isoxazole (9). Compound 9 has been investigated by luminescence spectroscopy. Ab initio and/or semiempirical (PM3) quantum-chemical calculations on the parent compounds la, 2a, 3a, b, the phenylsubstituted derivatives 1 b, 2b, 9, and on 4 in ground and excited states are performed.