We have investigated the cannibalistic self-trapping reaction of an ortho-benzyne derivativeg eneratedf rom 1,11-bis(p-tolyl)undeca-1,3,8,10-tetrayne in an HDDA reaction. Without adding anys pecific trapping agent, the highly reactiveb enzyne is trapped by anotherb isdiyne molecule in at least three different modes.W eh ave isolated and characterized the resulting products and performed high-level calculations concerning the reactionm echanism. During the cannibalistic self-trapping process, either aC Ct riple bond or an sp-sp 3 CÀCs ingle bond is cleaved. Up to seven rings and nine CÀCb onds are formed startingf rom two 1,11bis(p-tolyl)undeca-1,3,8,10-tetrayne molecules. Our experimentsa nd calculations provide considerable insight into the variety of reactionp athways which the ortho-benzyned erivative,g enerated from ab isdiyne, can take when reacting with another bisdiynem olecule.