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The photoluminescence of Au(I) complexes is generally characterized by long radiative lifetimes owing to the large spin-orbital coupling constant of the Au(I) ion. Herein, we report three brightly emissive Au(I) coordination compounds, <b>1</b>, <b>2a,</b> and <b>2b</b>, that reveal unexpectedly short emission lifetimes of 10–20 ns. Polymorphs <b>2a</b> and <b>2b</b> exclusively exhibit fluorescence, which is quite rare for Au(I) compounds, while compound <b>1</b> reveals fluorescence as the major radiative pathway, and a minor contribution of a microsecond-scale component. The fluorescent behaviour for <b>1</b>–<b>2</b> is rationalized by means of quantum chemical (TD)-DFT calculations, which reveal the following: (1) S₀–S₁ and S₀–T₁ transitions mainly exhibit an intraligand nature. (2) The calculated spin-orbital coupling (SOC) between the states is small, which is a consequence of overall small metal contribution to the frontier orbitals. (3) The T₁ state features much lower energy than the S₁ state (by ca. 7000 cm⁻¹), which hinders the SOC between the states. Thus, the S₁ state decays in the form of fluorescence, rather than couples with T₁. In the specific case of complex <b>1</b>, the potential energy surfaces for the S₁ and T₂ states intersect, while the vibrationally resolved S₁–S₀ and T₂–S₀ calculated radiative transitions show substantial overlap. Thus, the microsecond-scale component for complex <b>1</b> can stem from the coupling between the S₁ and T₂ states.