Long π-conjugated carbon chains that were the subject of the current review can be represented with the simplified onedimensional model of Su-Schrieffer-Heeger (SSH) . Here, the physical model disregards the presence of hydrogen atoms and the complex atomic structure surrounding carbon atoms. It assumes one electron per carbon atom, with an associated energy when localized on a carbon atom and an energy when the electron hops between atoms. Under this model, cumulene is represented as an evenly spaced one-dimensional atomic chain, while polyyne is modeled as a one-dimensional atomic chain with alternating bond lengths. This approach demonstrates that cumulene could behave as a metal (due to the absence of a band gap), whereas polyyne could act as a semiconductor with an open band gap.