Co-crystallisation of the anionic cyanometallate chromophore [Ru(bipy)(CN)4]2- with Yb(III) provides coordination polymers or oligomers containing Ru-CN-Yb bridges; in [K(H2O) 4][Yb(H2O)6][Ru(bipy)(CN)4] 2·5H2O Ru → Yb energy-transfer (k > 5 × 106 s-1) results in partial quenching of the Ru-based luminescence and sensitised near-IR luminescence from the Yb(III) unit.
