In this work, the swelling behaviours of the poly(ClNOEMA-co-DEAEMA) Langmuir-Blodgett (LB) films were investigated with respect to volatile organic compounds (VOCs) at room temperature by using Quartz Crystal Microbalance (QCM) method. The changes in resonance frequency associated with mass changes can be attributed to the swelling behaviour of copolymer thin films during vapor absorption. The diffusion coefficients are found to be 31.07 x 10−16, 15.61 x 10−16 and 1.22 x 10−16 cm2 s−1 for dichloromethane, chloroform, and benzene, respectively. The response of copolymer LB films to the choosed VOCs has been investigated in conditions of physical properties of the solvents, and the films were obtain to be largely sensitive to dichloromethane vapor compared to other studied vapors.