Naphthalene (Nap)-containing poly(diphenylacetylene)s with different spacer lengths (-{C6H5C=C[C6H4O(CH2)(m)O-Nap]}(n)-; P1(m), m = 4, 6, 8) are synthesized. The monomers are prepared by etherifications of 1,m-dibromoalkanes with 1-naphthol and 1-(4-hydroxy)phenyl-2-phenylacetylene and are polymerized by TaCl5-n-Bu4Sn and WCl6-Ph4Sn catalysts. Whereas the tantalum-based catalyst gives insoluble products in low yields, the tungsten-based catalyst furnishes soluble polymers with high molecular weights (M-w up to 5.0 x 10(4)) in satisfactory yields (up to 62%). The structures and properties of the polymers are characterized and evaluated by IR, NMR, TGA, UV, PL, and EL analyses. All the polymers are thermally stable: while the polymers lose 5% of their weights at similar to 420 degrees C under nitrogen, no decreases in molecular weights are found after they have been annealed at 200 degrees C for 2 h in air. When their THF solutions are photoexcited, the polymers emit strong green lights with high efficiencies (up to 98%). No significant shifts in the photoluminescence spectra are observed when the polymers are cast into thin solid films, suggestive of little involvement of aggregative or excimeric emission. A multilayer EL device with a configuration of ITO/P1(8):PVK/BCP/Alq(3)/LiF/Al is constructed, which emits a green light of 520 nm with a maximum external quantum efficiency of 0.16%. The spectral stability is outstanding: no recognizable change is observed in the EL spectrum when the device current is raised. Irradiation of a film of P1(8) through a mask photooxidizes and quenches the emission of the exposed regions, resulting in the formation of two-dimensional luminescent photopatterns. (c) 2006 Elsevier Ltd. All rights reserved.