Electron acceptor molecules form charge transfer (CT) complexes with electron donors. CT complexes are known as an organic conductive material. In this report, we suggest a nanowire sensor to detect electron-acceptive aromatic nitro compounds by conductance switching brought on by charge transfer interaction. The sensor surface possesses a molecular wire network formed by bridging nanogaps between Au nanoparticles (Au-NPs) with electron donor oligothiophene. The Au-NPs were fabricated by sputter deposition with controlling the particle-size and the gap-size. We confirmed the oligothiophene bridging by resistivity and the formation of CT interaction between oligothiophene and electron acceptors by fluorescence quenching. The conductance of the sensor electrode was increased by adsorption of electron acceptors, such as iodine and aromatic nitro compounds.