Molecular wires incorporating polypyridine metal complexes are amenable to studies of directional energy and electron transfer. The complexes are chromophores mainly based on Ru(II), Os(II), Rh(III), and Re(I) centres, which usually exhibit luminescence and can play as donor (D) or acceptor (A) units. A bridging ligand (B) provides both the structural and electronic connectivity between D and A and the DAB wires are flexible or rigid, depending on the spacers included within the bridge. Developments regarding multicentre systems and stereochemically interesting systems are taken into account.