Two alternating copolymers composed of a terphenylene unit and either a fluorenediylvinylene or a thiophenediylvinylene unit were synthesized by using a Wittig reaction. The products were poly[2′,5′-dihexyloxy-p-terphenyl-4,4″-ylenevinylene-alt-2,7-( 9,9′-di-n-hexylfluorene)diylvinylene] (A) and poly[2′,5′-dihexyloxy-p-terphenyl-4,4″-ylenevinylene-alt-(2,5- thiophenediylvinylene)] (B), respectively. The polymers were characterized by 1H NMR, 13C NMR, and elemental analysis. The polymers show good solubility in common organic solvents, and the films emit blue-green and green-yellow light, respectively, on irradiation with UV light. In addition to the fabrication and evaluation of EL devices using both A and B, the photoluminescence of mixtures of A with an organically modified clay was investigated.