3-[(<i>E</i>)-Benzylidene]indolin-2-one

In the title indolin-2-one derivative, C(15)H(11)NO, the phenyl ring and the oxoindoline fused-ring system (r.m.s. deviation = 0.011 Å) are aligned at 48.52 (6)°. In the crystal, inversion-related mol-ecules form an N-H⋯O hydrogen-bonded dimer via an eight-membered {⋯HNCO}(2) synthon. The dimeric aggregates are linked into a three-dimensional architecture via C-H⋯O and π-π inter-actions between the five- and six-membered rings of the fused ring system, with an inter-centroid distance of 3.4538 (8) Å.