We report the synthesis of a novel metal-organic capsule constructed from six pyrogallolarene macrocycles, which are switched together by 16 Fe(III) and 16 Co(II) ions. This supramolecular structure represents the first instance of a spheroidal heterometallic nanocage assembled through a one-step metal-ligand coordination approach. This new assembly also demonstrates an important proof of concept through the formation of multiple heterometallic metal-metal interactions within the capsule framework. Photophysical and electrochemical studies of self-assembled capsule films indicate their potential as semiconductors. These materials display unexpected photoelectric conversion properties, thus representing an emergent phenomenon in discrete metal-organic supramolecular assemblies.