This article reviews the synthesis and chemical properties of poly(aryleneethynyl- ene)s, PAEs, consisting of sulfur-containing heteroaromatic rings (e.g., thiophene), nitrogen- containing heteroaromatic rings (e.g., pyridine), and silicon-containing heteroaromatic rings (e.g., silole). The polymers are usually prepared via Pd-catalyzed C-C coupling between diethynyl compounds and dihalo organic compounds. However, synthesis using other monomers such as distannylacetylenic compounds is also possible. This article de- scribes the chemical and optical properties of PAEs, which are affected by the basic electronic properties of the heteroaromatic ring and the molecular structure of the PAE.