Controlling interactions among nanoparticles is paramount to achieving assemblies vital to technologies seeking to exploit their novel collective properties. Although various techniques have been advanced, robust ones are necessary for upscaling nanoparticle assembly and crystallization. Here, we show that by grafting gold nanoparticles (AuNPs) with charge-end-group-thiolated polyethylene-glycol, we control the charge of each AuNP. Such control facilitates formation of various two-dimensional structures of oppositely charged binary constituents at vapor/liquid interfaces. Using surface-sensitive synchrotron X-ray diffraction techniques, we establish the formation of distinct checker-board square lattice structures at a range of pH and molar ratios of the constituents. By regulating pH the superlattices can transform from square to the hexagonal lattice or vice versa and, to a single component superstructure at the interface. Our recipe for the control of charges and their consequent interactions among nanoparticles can be readily exploited in the assembly of devices in two and three dimensions.