1‐Acetyl‐3‐[1‐(4‐methoxyphenyl)‐2‐oxopropylidene]‐1H‐indol‐2(3H)‐one: a twinned crystal

The crystal of the title compound, C₂₀H₁₇NO₄, which was used for collecting intensity data was twinned. Each of the two crystallographically independent mol­ecules in the asymmetric unit has a planar indole moiety perpendicular to a planar oxo­propyl moiety. The distribution of the bonds at the central C atom joining the oxo­propyl, phenyl and indole substituents is also planar. The packing is stabilized by intermolecular C—H?O interactions, as well as by dipole–dipole and van der Waals interactions.