Platinum–ethynylflavone complexes featuring various polyether arms display ³IL phosphorescence associated with the appended flavone perturbed by the platinum centre (τ ∼20 μs), but switch dramatically to flavone-localised ¹IL fluorescence (τ ∼ 2 ns) upon selective binding of Pb²⁺.

Luminescent dinuclear Ir(iii) complexes of a bis-N^∧C^∧N-coordinating ligand are reported with two metal ions bound to a central pyrimidine. A pair of enantiomers and a meso form have been structurally characterised.

We present the synthesis and in-depth photophysical analysis of a di-Pt(II) complex with a ditopic bis-N^C^N ligand. The complex exhibits a dual luminescent behaviour by emitting simultaneously delayed fluorescence and phosphorescence. By comparing with the mono-Pt(II) analogue, we demonstrate that thermally activated delayed fluorescence (TADF) is turned on in the di-Pt(II) complex due to the occurrence of three main differences relative to the mono-Pt(II) analogue: a larger singlet radiative rate constant (k^S _r), a smaller singlet–triplet energy gap (ΔE_ST) and a longer phosphorescence decay lifetime (τ_PH). We observe similar trends among other di-Pt(II) complexes and conclude that bimetallic structures promote conditions favourable for TADF to occur. The diplatinum(II) complex also shows a long wavelength-emissive excimer which yields near infrared electroluminescence, λ_el = 805 nm, in a solution-processed OLED device with EQE_max = 0.51%. We believe this is the highest efficiency reported to date for an excimer Pt(II) emitter with λ_el > 800 nm in a solution-processed OLED device.

A versatile approach is introduced for the synthesis of well-defined, biocompatible conjugates combining two-photon chromophores and hydrophilic multifunctional polymers synthesized by RAFT controlled radical polymerization. As an illustration, two different classes of conjugates carrying multiple fluorophores (based on an anthracene moiety, Anth) or photosensitizers (based on a dibromobenzene moiety, DBB) along the polymer chain were elaborated for bioimaging and photodynamic therapy (PDT) applications, respectively. In both cases, the polymer greatly improved the solubility in biorelevant media as well as the cell uptake. Anth conjugates provided high quality fluorescence microscopy images using both one- and two-photon excitation. DBB conjugates potently induced the death of cancer cells upon photoactivation.