Poly(1-alkyne)s containing azobenzene pendants with different spacer lengths and ring substitutents -{HC=C(CH2)(m)COO-C6H4-N=N-C6H4-NO2])(n)- P1(m) m = 3, 8 and -{HC=C[(CH2)(m)COO-C6H3-o-Br-N=N-C6H4 NO2]}(n)- P2(m) m = 3, 8] are designed and synthesized. The polymers are prepared in satisfactory yields with high molecular weights (M-w up to 3.3 X 10(4) Da) by [Rh(nbd)Cl](2)-Et3N in THF or dioxane. Their structures and properties are characterized and evaluated by IR, UV, NMR, TGA, nonlinear optical and optical limiting analyses. All the polymers are completely soluble in common organic solvents and lose 5% of their weights at temperatures of similar to 270 degrees C. The spacer length and the pendant substitutent affect the nonlinear optical and optical limiting properties of the polymers, with 1(3) showing superior properties than its counterparts 1(8) and 2(3) with long methylene spacers and bromide substitutents on the azobenzene pendants, respectively. (c) 2005 Elsevier Ltd. All rights reserved.