Holmium (Ho)-based dimetallofullerene, Ho₂@C₈₂, has been synthesized and isolated by multistep HPLC, and the co-crystal of Ho₂@C₈₂ with decapyrrylcorannulene (DPC) was successfully grown by a slow evaporation of solvent. The molecular structure and the unique packing model of Ho₂@C₈₂ isomer in the co-crystal have been elucidated by X-ray crystal structure analysis. The isomeric C₈₂ cages of Ho₂@C₈₂ was unambiguously determined to be C_3v(8)-C₈₂. The shortest metal cage-carbon distance is 2.348(9) Å, and the Ho···Ho distance between the two opposite Ho sites is 3.599(6) Å. As an electrostatic consequence, the extra negative charges from DPC are mainly localized on these cage carbons far away from endohedral metal ion(s), which are of the lowest charge density values. Thus, endohedral metal atom(s) would favorably situate position(s) as far away from DPC molecules as possible. Moreover, the co-crystals demonstrate unique crystallographic packing two-dimensional layered structure, in which dimetallofullerene molecules are completely surrounded by five DPC molecules and aggregate in a sinusoidal wave fashion along one axis.