Scanning tunneling microscopy (STM) and low-energy electron diffraction were used to reveal the structures of ordered adlayers of [2+2]-type C-60-C-60 fullerene dimer (C-120) and C-60-C-70 cross-dimer (C-130) formed on Au(111) by immersingit in a benzene solution containing C-120 or C-130 molecules. High-resolution STM images clearly showed the packing arrangements and the electronic structures Of C-120 and C-130 on the Au(111) surface in ultrahigh vacuum. The (2root3 x 4root3)R30degrees, (2root3 x 5root3)R30degrees, and (7 x 7) structures were found for the C-120 adlayer on the Au(111) surface, whereas C-130 molecules were closely packed on the surface. Each C-60 or C-70 monomer cage was discerned in the STM image of a C-130 molecule.