2-[1-(1-Oxoindan-2-yl)ethyl]indan-1-one

In the title compound, C(20)H(18)O(2), the fused-ring systems are essentially planar (r.m.s. deviations of the nine fitted atoms = 0.009 and 0.027 Å) and exhibit an orthogonal relationship [dihedral angle = 79.83 (5)°]. To a first approximation, the ketone-O atoms are directed to opposite sides of the mol-ecule. A three-dimensional architecture arises in the crystal packing owing to C-H⋯O, C-H⋯π and π-π inter-actions [between centrosymmetrically related benzene rings with centroid-centroid distance = 3.7647 (10) Å].