The reaction of 3-allyl-1,5-dimethyl-1,5-benzodiazepine-2,4-dione and benzaldoxime leads to the title compound, C(21)H(21)N(3)O(3). The mol-ecular structure is built up from two fused six- and seven-membered rings linked to a chain including a five- and six-membered ring (isoxazoline and phen-yl) via a methyl-ene group. The seven-membered ring displays a boat conformation. The dihedral angle between the two six-membered rings is 74.3 (1)°.