An organic polymer that conducts electricity. Conducting polymers have a crystalline structure in which chains of conjugated unsaturated carbon-carbon bonds are aligned. Examples are polyacetylene and polypyrrole. There has been considerable interest in the development of such materials because they would be cheaper and lighter than metallic conductors. However, conducting polymers tend to be chemically unstable, thus making commercial application difficult. Despite this, some light-emitting diodes based on conducting polymers have been developed.