The bright side of triple double bonds: Two series of stable tridentate cyclometalated PtII and AuIII allenylidene complexes were found to exhibit many functionalities, such as long‐lived excited states, self‐assembly into supramolecular nanostructures, DNA and nucleus binding and cellular imaging capabilities (see figure).

A new class of dinuclear cyclometalated platinum(II) complexes with [Pt II (C^N^N)CNR] + (HC^N^N ¼ 6phenyl-2,2 0 -bipyridyl, CNR ¼ 2,6-dimethylphenyl isocyanide) motifs covalently connected by oligo(oxyethylene) chains form luminescent lyotropic chromonic liquid crystals or hydrogels in aqueous dispersions with intra-and intermolecular Pt/Pt and p-p interactions as the driving force. Their solution behaviour is modulated by the length of the oligo(oxyethylene) chain connecting the two cyclometalated platinum(II) motifs. One of the dinuclear Pt(II) complexes with a long oligo(oxyethylene) bridge and which does not display intramolecular Pt/Pt and p-p interactions can act as an effective 'gelling stimulus' for mononuclear [Pt II (C^N^N)CNR] + complexes in aqueous solutions, resulting in the formation of a nematic hydrogel that is persistent and displays red photoluminescence.