The synthesis of dispiro [4.0.4.4]tetradeca-11,13-dienes containing one or two heteroatoms (O,S) is described. In all cases, a suitably functionalized cyclohexanone served as the precursor. Bromination-dehydrobromination delivered the cyclohexenone, which was subjected to 1,2-reduction and elimination by reaction with 2,4-dinitrobenzenesulfenyl chloride and thermal activation. The pathways by which the 1,3-cyclohexadienes undergo acid-catalyzed isomerization have been identified. The choice between aromatization and conversion to a [4.4.4]propelladiene gives evidence for being dependent on an interplay between steric and electronic factors. The generation of a transient oxonium ion causes both pathways to operate at approximately equivalent levels. When a thermodynamically less favorable thionium ion intermediate is involved, selectivity increases to the point where only aromatization occurs in the presence of p-toluenesulfonic acid. A neighboring sulfhydryl group is shown to be capable of intercepting the spirocyclic carbocationic intermediate. The regiochemistry of the epoxidation of 30 and the stereoselectivity of Diels-Alder cycloaddition of the [4.4.4]propelladienes to N-methyltriazolinedione are also detailed.