A family of “two-in-one” dual-emissive complexes, [Mn(L)₃]MnHal₄, containing octahedral and tetrahedral Mn²⁺ ions in the single structure, is introduced.

A series of Cu(I) halide complexes derived from tris(2-pyridyl)phosphine (Py₃P), [Cu₂(Py₃P)₂X₂] (X = Cl, Br, I), have been synthesized by a straightforward reaction in solution or through a mechanochemical route. At room temperature, the solid complexes exhibit bright dual-mode photoluminescence (λ_max = 520–550 nm, τ = 14.5–20.0 μs, and Φ_PL ≈ 53%), expressed by thermally activated delayed fluorescence (TADF) combined with phosphorescence (PH), originating from ¹(M + X)LCT and ³(M + X)LCT excited states, respectively. Remarkably, the balance of these radiative processes at 300 K is regulated by halogen atom nature, switching from TADF-assisted phosphorescence to PH-admixed TADF. The emission of [Cu₂(Py₃P)₂Cl₂] at 300 K is largely contributed by PH (73%) admixed with the TADF fraction (27%) and [Cu₂(Py₃P)₂Br₂] also emits mainly PH (65%) admixed with the larger TADF fraction (35%). Meanwhile, for [Cu₂(Py₃P)₂I₂], the TADF channel becomes dominating (61%) and PH contribution drops to 39%. The photophysical study corroborated by (TD)DFT computations has revealed that this effect arises mainly from the narrowing of the ΔE(S₁ − T₁) gap of the [Cu₂(Py₃P)₂X₂] complexes in the order Cl (1500 cm⁻¹) > Br (1250 cm⁻¹) > I (1000 cm⁻¹) which facilitates the TADF pathway and suppresses PH in the same order.

A new Ag(I) complex based on tris(2-pyridyl)phosphine (Py₃P), [Ag₂(Py₃P)₃(SCN)₂], has been synthesized and chemically characterized. Theoretical calculations and photophysical investigations reveal thermally activated delayed fluorescence (TADF) coupled with outstanding solvato- and vapor-luminescent behavior. The parent complex [Ag₂(Py₃P)₃(SCN)₂] shows sky-blue TADF (λ_max = 469 nm) at ambient temperature with a quantum yield of Φ_PL = 16% and an emission decay time of 2.2 μs. Upon exposing the complex to CH₂Cl₂ or CHCl₃ vapors, [Ag₂(Py₃P)₃(SCN)₂]·0.66CH₂Cl₂ and [Ag₂(Py₃P)₃(SCN)₂]·CHCl₃ solvates are formed. This process is accompanied by a strong enhancement of the luminescence intensity. Both solvates also emit sky-blue TADF (λ_max = 478–483 nm), but the emission quantum yield reaches Φ_PL ≈ 70% at an emission decay time of 9–12 μs, depending on the solvent. According to DFT/TD-DFT computations, the observed TADF originates from a ¹(M + X)LCT excited state. The experimentally determined ΔE(S₁ − T₁) gap for [Ag₂(Py₃P)₃(SCN)₂]·0.66CH₂Cl₂ is relatively large and amounts to 1040 cm⁻¹ (≈129 meV).