The reaction of biphenyl-2,2'-diol with 1,1,2,2-tetrakis(bromomethyl)cyclopropane leads to two products, namely a propellane-type compound and a dispiro-type compound. The molecular structure of 4,5;6,7-dibenzo-3,8,12-trioxa[8.3.1]propellane has been determined previously by spectroscopic methods. The crystal structure of the dispiro product, 2,7,12,17-tetraoxa-3,4:5,6:13,14:15,16-tetrabenzodispiro[8.1.8.0]nonadecane, C(31)H(26)O(4), revealed that the conformations of the nine-membered heterocyclic rings are due to interactions between the pi-electron system of the biphenyl moiety and the lone electron pairs of the ether O atoms, the repulsion of the lone electron pairs of atoms O1...O2 and O3...O4, and steric interactions between H atoms in ortho positions. The conformations have C(1) symmetry and can be described approximately as twist-boat.