The optical properties of one mono-substituted polyacetylene and two di-substituted polyacetylenes have been investigated. Each of the substituted polyacetylenes bears a carbazole unit in the side chain. In spite of the differences in their molecular structures, the dilute solutions(about 1×10-6 M) of these substituted polyacetylenes exhibit the same absorptions and deep-blue emissions(about 360 nm). Interestingly, the absorption and emission spectra of these substituted polyacetylenes are similar to those of the small molecule carbazole. As the concentration of the substituted polyacetylenes increases to about 1×10-6 M, we have detected intense blue emissions at about 475 nm. Our results indicate that the absorption, the deep-blue emission(about 360 nm) and the intense blue emission(about 475 nm) originate from the carbazole chromophores in the side chain.
