[11]Cycloparaphenylene ([11]CPP) selectively encapsulates La@C-82 to form the shortest possible metallofullerene-carbon nanotube (CNT) peapod, La@C-82< subset of>[11]CPP, in solution and in the solid state. Complexation in solution was affected by the polarity of the solvent and was 16times stronger in the polar solvent nitrobenzene than in the nonpolar solvent 1,2-dichlorobenzene. Electrochemical analysis revealed that the redox potentials of La@C-82 were negatively shifted upon complexation from free La@C-82. Furthermore, the shifts in the redox potentials increased with polarity of the solvent. These results are consistent with formation of a polar complex, (La@C-82)(-)< subset of>[11]CPP+, by partial electron transfer from [11]CPP to La@C-82. This is the first observation of such an electronic interaction between a fullerene pea and CPP pod. Theoretical calculations also supported partial charge transfer (0.07) from [11]CPP to La@C-82. The structure of the complex was unambiguously determined by X-ray crystallographic analysis, which showed the La atom inside the C-82 near the periphery of the [11]CPP. The dipole moment of La@C-82 was projected toward the CPP pea, nearly perpendicular to the CPP axis. The position of the La atom and the direction of the dipole moment in La@C-82< subset of>[11]CPP were significantly different from those observed in La@C-82< subset of>CNT, thus indicating a difference in orientation of the fullerene peas between fullerene-CPP and fullerene-CNT peapods. These results highlight the importance of pea-pea interactions in determining the orientation of the metallofullerene in metallofullerene-CNT peapods.