A new polypyrrole-bromophenol blue (PPy-BPB) compound was synthesized in nanosphere and nanorod forms on quartz crystal microbalance (QCM) gold electrode by direct one-step electrochemical deposition, and utilized for highly sensitive determination of nitroexplosive compounds’ vapors in the ambient temperature in open air and through a home-made vapor generation/test system. A series of QCM sensors modified with PPy doped with different bromine containing anions and the regular chloride dopant were prepared and used for sensing of nitroexplosives. The design entailed a PPy-BPB modified QCM sensor with very low limit of detections for nitroexplosives including; 500 ppt (v) for TNT, 800 ppt (v) for PETN, 1 ppb (v) for RDX and 2 ppb (v) for HMX. The sensor showed great promise for eventual commercial use due to its robust nature. The selectivity of PPy-BPB QCM sensor for nitroexplosives was studied compared to a large number of interferents extending from laboratory environment (most of general solvents, nitromethane and amines) to real sample matrices including plasticizers (phthalates) to gasoline and diesel fuel and the results exhibited a very significant selectivity toward nitroexplosive compounds. The sensor presented to be stable, with fast response time and readily reversible at room temperature.