[reaction: see text] A shape-persistent, conjugated o-phenylene ethynylene cyclic trimer was prepared in one step from tetrasubstituted benzene monomer 4 in 86% isolated yield through precipitation-driven alkyne metathesis. The template-free, selective generation of the molecular triangle 5 is a thermodynamically favored process and under equilibrium control. A novel tetrameric macrocycle 7 was generated via scrambling metathesis between tricycle 5 and hexacycle 6 using this dynamic covalent chemistry.
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