The design of highly near-infrared (NIR) emissive lanthanide (Ln) complexes is challenging, owing to the lack of molecular systems with a high sensitization efficiency and the difficulty of achieving a large intrinsic quantum yield. Previous studies have reported success in optimizing individual factors and achieving high overall quantum yields, with the best yield being 12% for Yb(III). Herein we report a series of highly NIR emissive Yb complexes, in which the Yb is sandwiched between an octafluorinated porphyrinate antenna ligand and a deuterated Kläui ligand, which allowed optimization of two factors in the same system, and one of the complexes had an unprecedented quantum yield of 63% (estimated uncertainty 15%) in CD₂Cl₂ with a long lifetime (τ_obs) of 714 μs. Systematic analysis of the structure–photophysical properties relationship suggested that porphyrinates are effective antenna ligands with a sensitization efficiency up to ca. 100% and that replacement of the high-energy C–H oscillators in porphyrinate and Kläui ligands significantly improves the intrinsic quantum yield up to 75% (τ_obs/τ_rad), both of which contribute to enhancing the NIR emission intensity of Yb(III) up to 25-fold. Besides the high luminescence efficiency, these Yb complexes have other attractive features such as excitation in the visible range and large extinction coefficients which make these Yb(III) complexes outstanding optical materials in the NIR region.

We report three synthetic methods to prepare biocompatible Yb ³⁺ complexes, which displayed high NIR luminescence with quantum yields up to 13% in aqueous media. This renders β-fluorinated Yb ³⁺ porphyrinoids a new class of NIR probes for living cell imaging including time-resolved fluorescence lifetime imaging.

Reversibly switchable fluorescent proteins (RSFPs) have attracted widespread interest for emerging techniques including repeated tracking of protein behavior and superresolution microscopy. Among the limited number of RSFPs available, only Dronpa is widely employed for most cell biology applications due to its monomeric and other favorable photochemical properties. Here we developed a series of monomeric green RSFPs with beneficial optical characteristics such as high photon output per switch, high photostability, a broad range of switching rate, and pH-dependence, which make them potentially useful for various applications. One member of this series, mGeos-M, exhibits the highest photon budget and localization precision potential among all green RSFPs. We propose mGeos-M as a candidate to replace Dronpa for applications such as dynamic tracking, dual-color superresolution imaging, and optical lock-in detection.

A novel class of ZnSalens (ZnL₁1_–10–10) with lipophilic and cationic conjugates as optical probes in single and two-photon fluorescence microscopy images of living cells were prepared, which exhibited chemo- and photostability, low cytotoxicity and high subcellular selectivity.