A mixture of 4,4'-[(1,2-ethanediyl)bis(oxy)bis(3-methoxybenzaldehyde)] (49.5 g, 0.15 mol), methyl cyanoacetate (30 g, 0.30 mol), N,N-dimethylformamide (500 mL), piperidine (3 mL) and acetic acid (1 mL) is heated with stirring at about 100° C. for 2 hours. The reaction mixture is allowed to cool to room temperature and the pale yellow solid which forms is collected by filtration and washed with methanol. The crude product is reslurried in 500 mL of boiling methanol, collected by filtration, washed with methanol and dried in air. A yield of 59.4 g (81% of theory) of dimethyl 3,3'-[(1,2-ethanediyl)bis(oxy)bis(3-methoxy-4,1-phenylene)bis(2-cyano-2-propenoate)] having the formula: ##STR14## is obtained. The bis-methine compound has an absorption maximum (λmax) at 365 nm in methylene chloride in the UV absorption spectrum (ε=46,856).
