The asymmetric unit of the title compound, C(19)H(16)N(2)O(3), comprises three independent mol-ecules (A, B and C). The inversion-related molecule of A is virtually superimposable upon the other two molecules. In each mol-ecule, there is a twist in the link between the approximately syn carbonyl and amine groups [the N-C-C-O torsion angles range from 19.73 (19) to -21.2 (2)°]. Each mol-ecule has a bent shape quanti-fied in terms of the dihedral angle between the indole and indole fused-ring systems [range = 45.69 (5)-47.91 (5)°]. In the crystal, the A and B mol-ecules form dimeric aggregates via ten-membered {⋯HNC(2)O}(2) synthons, while the C mol-ecules self-associate similarly but about a centre of inversion.