Abstract In the present article we report about the Langmuir–Blodgett thin film characterization and organic vapor sensing properties of LB film properties of three oxygen-linked phthalocyanines incorporating lutetium (Pc 2 Lu). UV–visible spectroscopy and quartz crystal microbalance are used for the characterization of Pc 2 Lu material. Our results show that high quality and uniform LB films can be prepared with the transfer ratio ∼0.95 and this material is found more sensitive to chloroform and isopropyl alcohol vapors than other organic vapors used in this work. The response, in terms of frequency change to the exposure of these vapors, is fast, large and reversible.