The cobalt phthalocyanine (CoPc) resistance-type sensors to NO2 were prepared using CoPc thin films via interfacial self-assembly method. Their sensing performances were investigated with respect to different NO2 concentrations from 1 to 50 ppm. It was found that the CoPc sensors show excellent sensing performance: relatively low temperature (115 degrees C), high sensitivity (2.7-10 ppm NO2 with a detection limit of 1 ppm), fast response and recovery (response time similar to 26 s and recovery time similar to 34 sat 3 ppm of NO2), and excellent stability (almost the same after 4 weeks), reliability and selectivity towards NO2. Further, the sensitivity showed a quasilinear relationship versus the concentration of NO2 in the ranges of 1-50 ppm. On account of their high performances, the prepared CoPc thin films via interfacial self-assembly method will provide a high-efficiency sensor for practical NO2 sensing applications.