2, 2'-Diiodobiphenyl and 5, 5'-dinitro-2, 2'-dihalobiphenyls underwent palladium-catalyzed phenylethynylation with 2 mol of phenylacetylene to yield 3-(fluoren-9-ylidene)-1, 3- diphenylpropyne and 3-(3, 6-dinitrofluoren-9-ylidene)-l, 3-diphenylpropyne, respectively. These fluorenyl compounds exhibited well-defined splitting patterns for the fluorenyl ring protons in the 250-MHz proton NMR spectra. The structure of 3-(fluoren-g-ylidene)-1, 3- ...