Blodgett films of copper(II) [tetrakis((3,3-dimethylbutoxy)carbonyl)]phthalocyanine and copper(II)[tetrakis(n-butoxycarbonyl)]phthalocyanine have been studied as sensitive elements of gas sensors. Moreover, alternate LB films of the two compounds and LB films obtained from a 1:1 mixture of them have also been investigated. In particular, after exposure to NO2 oxidizing gas, the electrical conductivity of the materials goes through a maximum at a temperature of about 170 degrees C corresponding to the maximum sensitivity to the gas. The sensitivity and stability of the response of the active layers to NO2 are discussed as well as the application of these materials as the sensitive elements for gas-sensing devices.