Methyl 3,4-di-(2'-hydroxyethoxy)benzylidenecyanoacetate (3) was prepared by hydrolysis of methyl 3,4-di-(2'-vinyloxyethoxy)benzylidenecyanoacetate (2). Diol 3 was condensed with 2,4-toluenediisocyanate, 3,3'-dimethoxy-4,4'-biphenylene-diisocyanate, and 1,6-hexamethylenediisocyanate to yield polyurethanes 4-6 containing the nonlinear optical chromophore 3,4-dioxybenzylidenecyanoacetate. The resulting polyurethanes 4-6 were soluble in common organic solvents such as acetone and dimethylformamide. Polymers 4-6 indicated thermal stability up to 300 degreesC in thermogravimetric thermograms with glass-transition temperature values obtained from differential scanning calorimetric thermograms in the range of 78-102 degreesC. The second-harmonic generation coefficients (d(33)) of the poled polymer films were around 6.9 x 10(-9) esu.