The iodocyclization of (iodoethynyl)benzoate via the 5-exo-dig pathway affords (diiodomethylene)isobenzofuran-1(3H)-one. The Sonogashira cross-coupling of the diiodide proceeds stereoselectively by the substitution of one iodine atom and protodeiodination of the second one, giving Z-isomers of alkynylated derivatives. The arylacetylenes coupling products exhibit fluorescence with an aggregation-induced emission enhancement. The coupling products of Z-3-(TMS-ethynyl)methylenephthalid and 1,4-diiodo-2,5-bis(octyloxy)benzene with extended π-systems underwent fast isomerization, giving equilibrium mixtures of isomers and exhibiting strong fluorescence in nonaggregating solvents.