A main-chain liquid-crystalline polymer based on an unsymmetrically disubstituted cyanostilbene has been synthesized and characterized. The polymer exhibited a highly birefringent nematic texture, followed at higher temperatures by a uniaxial nematic structure the scattering characteristics of which were two to three orders of magnitude smaller than those normally observed in liquid-crystalline materials. Thin solid films prepared by rapid cooling of the polymer in the monotropic state retained the molecular organization and scattering behaviour of this phase. A preliminary evaluation of the second-order nonlinear optical properties associated with these film structures was carried out by means of a crossed polarizer technique. © 1993.