A functionalized aromatic polyimide with a pendent nonlinear optical chromophore has been synthesized. The detailed characterization indicated very promising features for this polymer. The poly(amic acid) is soluble in several aprotic polar solvents, permitting thin film processing. The poly(amic acid) can be imidized at ca. 200 degrees C without damaging the NLO chromophore. A glass transition temperature of 240 degrees C was observed for the polyimide, which rendered a high stability of the optical nonlinearity at elevated temperatures, Long-term stability was observed at 170 degrees C.