Crystal structures of (12E)-12-(4-benzylidene)7,7,16-trimethyl-3-(4-methylphenyl)-1-oxa-16-aza - tetracyclo[11.2.1.0(2,11).0(4,9)]hexadeca-2(11),4(9)dien-5-one and (12E)-12-(4-bromobenzylidene)-73(4-bromophenyl)-,7,16-trimethyl-10-oxa-1 6-aza- tetracyclo[11.2.1.0(2,11).0(4,9)]hexadeca-2(11),4(9)dien-5-one

The title compounds, C32H35NO2, (I), and C30H29Br2NO2, (II), differ by the presence of a bromine atom instead of a methyl atom in the para position of two benzene rings of compound (II). The two compounds have a structural overlap r.m.s. deviation of 0.27 A degrees. The pyran and seven-membered cycloheptene rings in both structures adopt boat and boat-sofa conformations, respectively. Intra- and intermolecular C-H...O hydrogen bonds are responsible for the consolidation of the crystal packing of both molecules. In addition to this, weak C-H...pi interactions are also observed. The intermolecular interactions were quantified and analysed using Hirshfeld surface analysis.