Polymers composed of macromolecules containing exclusively alternating phenylene or substituted phenylene and ethene-1,2-diyl (formerly vinylene) or substituted ethene-1,2-diyl constitutional repeating units in the backbone: where \(\ce{R^{1}}\), \(\ce{R^{2}}\), \(\ce{R^{3}}\), \(\ce{R^{4}}\), \(\ce{R^{5}}\) and \(\ce{R^{6}}\) are each hydrogen, alkyl, aryl, heteroaryl, halogen, trialkylsilyl, etc. (structure-based polymer class name).