A new poly(aryleneethynylene) was synthesized from the palladium-catalyzed carbon-carbon coupling condensation of 4-[(tert-butyldimethylsiloxy)methyl]-1,6-heptadiyne and p-diiodobenzene. This polymerization proceeded well in mild reaction conditions to give a high yield of polymer (92%). The polymer structure was characterized by such instrumental methods as infrared and NMR spectroscopies. This polymer was completely soluble in common organic solvents such as chloroform, chlorobenzene, toluene, and xylene. The X-ray diffractogram of polymer powder showed that this polymer is amorphous. In the DSC thermogram of polymer, a broad exothermic peak was observed around 205 degrees C (started at 140 degrees C) in the first heating, whereas there was no exothermic peak in the second heating. When this polymer was excited at 272 nm, it gave PL maximum emissions at 327 and 380 nm.