4-tert-Butyl-2-[2-(1,3,3-trimethyl-indolin-2-yl-idene)ethyl-idene]cyclo-hexa-none.

The title mol-ecule, C(23)H(31)NO, has two alternative cyclo-hexa-none configurations at the 4-position in a ratio of 0.663 (3):0.337 (3). The plane of the five-membered planar ring in the indolin-2-yl-idene subtends an angle of 2.19 (7)° with its fused aromatic ring, an angle of 16.24 (8)° with the plane of the major cyclo-hexa-none configuration and an angle of 8.54 (15)° with the bridging planar ethyl-idene C atoms. These last atoms subtend an angle of 8.37 (16)° with the mean plane through the major cyclo-hexa-none configuration. The mol-ecules pack approximately parallel to the ([Formula: see text]01) plane via C-H⋯π and C-H⋯O inter-actions.