The title benzoxazine molecule, C 18 H 18 Br 2 N 2 O 2 , was prepared by a Mannich-type reaction of 4-bromophenol with ethane-1,2-diamine and formaldehyde. The title compound crystallizes in the monoclinic space group C 2/ c with a centre of inversion located at the mid-point of the C—C bond of the central CH 2 CH 2 spacer. The oxazinic ring adopts a half-chair conformation. The structure is compared to those of other functionalized benzoxazines synthesized in our laboratory. In the crystal, weak C—H...Br and C—H...O hydrogen bonds stack the molecules along the b- axis direction.