Merocyanine dye(MD) can be spread with poly(gamma-benzyl L-glutamate)/poly(ethylene oxide)/poly(gamma-benzyl L-glutamate)(PBLG/PEO/PBLG) onto the air-water interface from a solvent in which the copolymer assumes a helical conformation. The expanded isotherm of the copolymer changed into compressed one with mixing of MD in the copolymer monolayer. Langmuir-Blodgett(LB) assemblies can be built up from copolymer/MD mixture layer when the helical axes of the polypeptide chains are oriented in the compression direction. The dichroic absorption of the copolymer/MD mixtures indicates that dyes are located with a preferential orientation of their molecular axes with regard to the director axis of the polypeptide.