An unusual oligomerization/oxidation reaction of a 3‐boron‐substituted 1‐phenylbuta‐1,3‐diene produces 6,9,16,19‐tetraphenyl‐5,15‐distyryl‐3,13,25,26‐tetraoxa‐2,12‐diborapentacyclo[16.2.2.28,11.12,5.112,15]hexacosa‐1(20),7,10,17‐tetraene

The unusual title macrocyclic structure, C₆₀H₅₄B₂O₄, has been isolated from exposure of 3‐BF₃‐1‐phenylbuta‐1,3‐diene to both air and moisture in an attempt to obtain crystals of the starting butadiene compound. Formation of the macrocycle from six molecules of the starting butadiene material is rationalized and its structural features are compared with those of other B(OR)₂‐substituted cyclohexane and benzene ring containing structures. Molecules reside on crystallographic centers of inversion and there are no intermolecular interactions of note in the crystal structure.