The condensation of diisopropyl squarate and related cyclobutene-1,2-diones with 2 equiv of the same alkenyl anion or 1 equiv each of two different alkenyl anions can be a very effective method for the highly stenocontrolled synthesis of di-, tri-, and tetraquinanes. Two reaction cascades have been identified, The most prevalent and often exclusive reaction course is triggered by trans 1,2-addition of the two nucleophiles. Two consecutive conrotatory processes subsequently arise to deliver a doubly charged eight-membered ring intermediate, protonation of which leads to transannular adolization. The second option begins with cis 1,2-addition, this event triggering structural reorganization via a dianionic oxy-Cope rearrangement, When the alkenyl anions are sufficiently substituted, the two pathways are distinguishable on stereochemical grounds, A minor pathway consisting of trans 1,4-addition is seen to operate in certain contexts, especially when the alkenyllithium is "soft". Acetylide anions can also be utilized successfully; in such cases, the benefit of regiocontrolled protonation surfaces and gives rise to a single product, Other aspects of these complex tandem reactions have been investigated and are discussed.