The title molecule, C₂₄H₂₆N₂O₂, has its central C=C double bond placed on an inversion centre, and both indolin-2-one units are coplanar. The three terminal C atoms of the two butyl groups are disordered over two positions; the site occupancy factors are ca. 0.54 and 0.46. The central C=C bond exhibits an E configuration and is conjugated with the indole heterocycles. This aromatic character is related to the planarity of the isoindigo core and is reminiscent of that observed in stilbene.