Poly [1-(2-methoxyphenyl)penta-1,3-diyn-5-ol] ((1,2)-PMDO) was prepared by NbCl5/(n-Bu)(4)Sn-catalyzed metathesis. The 2:3 (1,2)-PMDO/poly(methyl methacrylate) (wt./wt.) film showed a conductivity of about 10(-3) S/cm after ferric chloride (FeCl3) doping. Third-order nonlinear optical susceptibility (chi((3))) Of (1,2)-PMDO was evaluated from third-harmonic generation by the Maker fringe method.