The intense research activity in the field of nanoparticles is motivated by the search for new materials in order to further miniaturize electronic devices, as well as by the fundamental question of how molecular electronic properties evolve with increasing size in this intermediate region between molecular and solid-state physics. In this respect, molecularly bridged nanoparticle aggregates have been attracting growing interest. The properties of two-dimensional assemblies of metal nanoparticles are controlled by the composition, geometry, and spatial arrangement of the nanoparticle building blocks. Such structures have been used for a variety of important applications in catalysis, photonics, electronics, and biological sensing. The 2D/3D control over the spatial arrangement of nanoparticles is primarily based on the thiolamphilic nature of metal nanoparticles, hydrogenbonding interactions, the highly specific recognition interaction of antigens/antibodies, and specific base-pairing interactions between DNA and its complementary strand. The liquid/liquid interface has also served as a fertile medium for nanoparticle assembly. Recently, Kumar et al. have observed that aromatic molecules such as benzene and anthracene present in the organic phase bind strongly with aqueous gold nanoparticles. This process leads to the immobilization of the gold nanoparticles in the form of a highly localized film at the interface. Most recently, Reincke and co-workers reported that the introduction of ethanol can pull hydrophilic citrate-stabilized Au-nanoparticles into the water/heptane interface, leading to a closely packed monolayer. Meanwhile, Duan et al. directed the assembly of hydrophobic and hydrophilic nanoparticles at water/oil interfaces by capping the nanoparticles with organic ligands. These reports demonstrate a promising way to create a 2D arrangement of hydrophobic or hydrophilic nanoparticles at water/oil interfaces. Based on these previous studies, we have developed a new high-throughput wet chemical method to fabricate 2D array of metal nanoparticles. We found that an appropriate ligand, 4'-aminobenzo-15-crown-5 hydrotetrafluoroborate (L) (Figure 1a), can mediate the self-assembly of gold nanoparticles (AuNPs) at the liquid/liquid interface in the form of a stable nanocomposite film.