Dynamic interactions and electronic processes in macromolecule-metal complexes established in 1970s provided conceptual basis for the development of a new class of functional polymers. Principles of soft/multiple interaction and multielectron processes have been pursued by exploring the macromolecule-metal complexes and polyion complexes, which gave rise to more generalized concept of macromolecular complexes. As one of the multiple interaction, reversible binding of O2 in aqueous media and facilitated transport of O2 were first accomplished by macromolecular metal complexes. The related oxygen technologies have led to the development of unprecedented materials to allow oxygen enrichment in cathodes of fuel cells and air batteries. Properties of electric/ionic conduction and electron transfer mediation in macromolecular complexes suggested our avenue toward the “radical batteries” as entirely organic, rare metal-free, and rechargeable burst power sources. Combination of the photoelectrochemistry of macromolecular complexes and the methods for the precision control of charge separation, transport, and storage in polymers derived from the battery research have inspired design principles of novel photovoltaic polymers useful for organic solar cells. In this paper, recent developments of energy-related materials originated from the idea of the macromolecular complexes are focused.