1,2-bis(3-ethynylphenyl)ethyne

3,3'-bis[(5''-tert-butylsulfanyl-2''-iodophenyl)ethynyl]tolane

3,3'-bis[(5''-tert-butylsulfanyl-2''-nitrophenyl)ethynyl]tolane

3-{[5''-tert-butylsulfanyl-3''-(4'''-ethynyl-2'''-nitrophenyl)ethynyl]phenylethynyl}-3'-(5''''-tert-butylsulfanyl-2''''-iodophenylethynyl)tolane

3-{[5''-tert-butylsulfanyl-3''-(2''',3'''-dinitro-4'''-trimethylsilylethynylphenyl)ethynyl]phenylethynyl}-3'-(5''''-tert-butylsulfanyl-2''''-iodophenylethynyl)tolane