In the title compound, C₇₂H₈₀N₂·C₇H₈, the acenaphthene ring system is essentially planar, with a maximum deviation of 0.041 (3) Å. The benzene rings bonded to the the N atoms are essentially parallel, forming a dihedral angle of 0.80 (11)°, and these rings form dihedral angles of 87.49 (9) and 88.25 (10)° with the mean plane of the acenaphthene ring system. The methyl C atoms of three of the isopropyl groups are disordered of two sets of sites of equal occupancy.

The title mol­ecule, C₆₄H₈₀N₂, lies on an inversion center wherein the central butane­diimine fragment [N=C(Me)-C(Me)=N] is essentially planar [maximum deviation = 0.002 (2) Å] and its mean plane forms a dihedral of 70.88 (10)° with the attached benzene ring. In the symmetry-unique part of the mol­ecule, the dihedral angles between the benzene ring bonded to the N atom and the other two benzene rings are 89.61 (6) and 82.77 (6)°.