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Herein, we report the inaugural instance of N‐heterocyclic silylene (NHSi)‐coordinated copper amide emitters (2–5). These complexes exhibit thermally activated delayed fluorescence (TADF) and singlet‐triplet dual emission in anaerobic conditions. The NHSi‐Cu‐diphenylamide (2) complex demonstrates TADF with a very small ΔEST gap (0.01 eV), an absolute quantum yield of 11 %, a radiative rate of 2.55×105 s−1, and a short τTADF of 0.45 μs in the solid state. The dual emissive complexes (3–5) achieve an absolute quantum yield of up to 20 % in the solid state with a kISC rate of 1.82×108 s−1 and exhibit room temperature phosphorescence (RTP) with lifetimes up to 9 ms. The gradual decrease in the intensity of the triplet state of complex 3 under controlled oxygen exposure demonstrates its potential for future oxygen‐sensing applications. Complexes 2 and 3 have been further utilized to fabricate converted LEDs, paving the way for future OLED production using newly synthesized NHSi‐Cu‐amides. [ABSTRACT FROM AUTHOR]

Organic-inorganic hybrid metal halides have become enormously important in optoelectronics, sensing, photosensitization, etc. In this study, we report a structural transition from a staircase configuration to a cubane configuration in Cu(I) iodide-based polymers influenced by the coordination behavior of two different π*-acceptor ligands. The staircase polymer structure, coordinated with 3-cyanopyridine, demonstrates efficient thermally activated delayed fluorescence from (metal+halide)-to-ligand charge transfer [ 1/3 (M+X)LCT] states, with a singlet-triplet energy splitting of ∼9 meV. Conversely, upon replacement of the cyano with an amino group at the same position, a one-dimensional polymeric structure of Cu 4 I 4 cubane-type clusters is formed, which shows strong cluster-centered ( 3 CC) orange emission at room temperature. Temperature-dependent photoluminescence studies indicate that the 3 CC state behaves as a self-trapped excitonic state with significant exciton-phonon coupling having a Huang-Rhys factor of 58.6. Additionally, we report this cubane-type cluster polymer acts as an efficient nonlinear optical material showing third harmonic generation with a χ (3) value of 1.32 × 10 -18 m 2 V -2 and a laser-induced damage threshold of 25.87 GW/cm 2 .