In order to reveal the electron transport properties of 2D superlattices of small nanoparticles, establishing a general fabrication technique of well-ordered small metal nanoparticle superlattices with narrow interparticle spacings (small tunneling resistance) is indispensable. We have succeeded in the fabrication of self-assembled 2D superlattices of small Au nanoparticles stabilized by bidentate thiolate ligands terminated with π-conjugated aromatic groups with tuning the interparticle spacings. The stable and monodisperse Au nanoparticles smaller than 2 nm are easily prepared by the reduction of HAuCl4•4H2O in DMF/H2O in the presence of a series of bidentate ligands, 2,6-bis(1′-(n-thioalkyl)benzimidazol-2-yl)pyridine. These small nanoparticles form hexagonal close packed (hcp) 2D superlattices with tunable interparticle spacings (1.2 nm to 2.5 nm), produced by changing the length of the ligand at not only the hydrophobic amorphous carbon but also the air-water interface. Long-range ordered hcp 2D superlattices were fabricated through the cleavage and construction of interligand π-π interactions formed via an annealing process at the air-water interface.