The title compound, C(26)H(28)O(3)Si, is an allylic oxidation product of the tert-but-yl(2,2-dimethyl-2,3-dihydro-benzo-furan-7-yl-oxy)diphenyl-silane with N-bromo-succinimide and 2,2'-azobis-isobutyronitrile. The nine-atom bicyclic system is almost planar, with an r.m.s deviation of 0.0123 (2) Å and a maximum deviation of 0.031 (2) Å for the O atom. In the crystal, the mol-ecules pile up along the b axis but the strongest inter-molecular contacts are the π-π stacking inter-actions between the benzene rings along the c axis [centroid-centroid distance = 3.655 (3) Å].