A highly efficient HDDA-Wittig coupling strategy for the synthesis of fully functionalized benzenes, such as ethyl 2-methylbenzoates and o-tolylethanones, is reported. The formation of four new C–C bonds via a one-pot, multicomponent cascade proceeded through the formation of a benzyne intermediate by self-cyclization, which then reacted with a phosphorus ylide. The target bicyclic aromatic compounds were prepared by the reaction of tetraynes with (acetylmethylene)triphenylphosphorane/(carbomethoxymethylene)triphenylphosphorane, and trace water allowed direct methylation and played a pivotal role in the construction of the natural carbonylated 2,3-dihydro-1H-indene cores, which were highly substituted. This report describes a robust method for the production of fused polyfunctional aromatic hydrocarbons.