A chromophore for nonlinear optics with extended conjugation has been synthesized, and its structure determined from X-ray diffraction data. The compound crystallizes in the monoclinic system with the space group P21/n and Z = 4. The unit cell parameters are a = 10.7826(4) Å, b = 14.5943(5) Å, c = 15.3792(5) Å and beta = 96.213(2)°. A thin film containing 5% of the chromophore in amorphous polycarbonate when poled at 180°C and 60 V/μm yields a maximum r33 value of 206 pm/V. This is seven times higher than the value found for the archetypical inorganic material, lithium niobate. [ABSTRACT FROM AUTHOR]