Metal nanoparticles and nanostructured materials exhibit unique electronic properties for applications in chemical sensors. This presentation focuses on a study of the detection of volatile organic compounds (VOCs) using nanostructure-coated chemiresistor sensor arrays. In addition to discussing the correlation between interparticle properties and electrical properties for molecularly-mediated thin film assemblies of nanoparticles, the sensor array responses to VOCs and the comparison with FID detector in gas chromatography will be described. The comparison is directed towards assessing the sensing performance in terms of sensitivity, selectivity and limit of detection of the nanostructured sensing materials. The achievement of high selectivity is a challenging task especially in a complex sensing environment, which is addressed by sensing arrays constructed from nanoparticle-assembled thin films on chemiresistors. Implication of the results to the correlation between the nanostructural parameters and the sensing performance will also be discussed.