Two-dimensional (2D) superlattices of mercaptosuccinic acid-modified gold nanoparticles were constructed at an air/water interface in the presence of 4-pyridinecarboxylic acid (PyC). Hydrogen-bonding interaction caused the incorporation of PyC into the surface-functionalized gold nanoparticles, suggesting that the interparticle spacing in the superlattices is controllable with an intercalating molecule.