At first look, the results from our dimer calculations are at odds with the crystal structure seen experimentally for B11, as B11's crystal structure has columns of window-to-arene packing that were calculated to be much higher in energy (> 30 kJ mol -1 ) than windowto-window arrangements. However, due to the rotation of the arenes on the vertices to maximise π -π overlap, the packing at one of the windows of the cage affects the packing behaviour at the other windows beyond purely steric considerations.