Two-photon-pumped dye lasers are very important because of their applications in wavelength up-conversion, optical data storage, biological imaging and photodynamic therapy. Such lasers are very difficult to realize in the solid state because of the aggregation-caused quenching. Here we demonstrate a new two-photon-pumped micro-laser by encapsulating the cationic pyridinium hemicyanine dye into an anionic metal-organic framework (MOF). The resultant MOF⊃dye composite exhibits significant two-photon fluorescence because of the large absorption cross-section and the encapsulation-enhanced luminescent efficiency of the dye. Furthermore, the well-faceted MOF crystal serves as a natural Fabry–Perot resonance cavity, leading to lasing around 640 nm when pumped with a 1064-nm pulse laser. This strategy not only combines the crystalline benefit of MOFs and luminescent behaviour of organic dyes but also creates a new synergistic two-photon-pumped lasing functionality, opening a new avenue for the future creation of solid-state photonic materials and devices.

The realization of porous materials for highly selective separation of acetylene (C2H2) from various other gases (e.g., carbon dioxide and ethylene) by adsorption is of prime importance but challenging in the petrochemical industry. Herein, a chemically stable Hofmann‐type metal−organic framework (MOF), Co(pyz)[Ni(CN)4] (termed as ZJU‐74a), that features sandwich‐like binding sites for benchmark C2H2 capture and separation is reported. Gas sorption isotherms reveal that ZJU‐74a exhibits by far the record C2H2 capture capacity (49 cm3 g−1 at 0.01 bar and 296 K) and thus ultrahigh selectivity for C2H2/CO2 (36.5), C2H2/C2H4 (24.2), and C2H2/CH4 (1312.9) separation at ambient conditions, respectively, of which the C2H2/CO2 selectivity is the highest among all the robust MOFs reported so far. Theoretical calculations indicate that the oppositely adjacent nickel(II) centers together with cyanide groups from different layers in ZJU‐74a can construct a sandwich‐type adsorption site to offer dually strong and cooperative interactions for the C2H2 molecule, thus leading to its ultrahigh C2H2 capture capacity and selectivities. The exceptional separation performance of ZJU‐74a is confirmed by both simulated and experimental breakthrough curves for 50/50 (v/v) C2H2/CO2, 1/99 C2H2/C2H4, and 50/50 C2H2/CH4 mixtures under ambient conditions.

The first luminescent two-dimensional MOF nanosheets NTU-9-NS Ti2(HDOBDC)2(H2DOBDC) (H2DOBDC=2,5dihydroxyterephthalic acid) fabricated via top-down delamination have been realized for fast-response and highly sensitive sensing of Fe 3+ . The highly dispersive nature and high accessible active sites on the surface of the 2D NTU-9-NS nanosheets enable them to have close contact with targeted metal ions, which led to fast-response and highly sensitive sensing of Fe 3+ ions, with the response time within seconds and the best detection limit performance of 0.45 µM among MOF materials. The fast-response and highly sensitive Fe 3+ sensing based on the NTU-9-NS nanosheets sensor material highlights the very promise of luminescent sensing applications of two-dimensional MOF nanosheet approach. This work contributes to develop the research on two-dimensional MOF nanosheets materials with targeted and specific recognition for the biological and environmental luminescent sensors.