In conclusion, we have demonstrated the preparation of TPE-derived imidazo[1,5-α]pyridinium salt H₄-L(PF₆)₄, which was used for accessing dinuclear silver(I) and gold(I) tetracarbene metallacycles [Ag₂L](PF₆)₂ and [Au₂L](PF₆)₂. The initially weakly emissive H₄-L(PF₆)₄ exhibited a remarkable enhancement of fluorescence intensities upon metalation to form the dinuclear silver(I) and gold(I) tetracarbene complexes in dilute solution. Upon the gradual addition of water as a poor solvent to the acetonitrile solution of TPE-derived complexes, the precursor H₄-L(PF₆)₄ exhibited typical AIE characteristics. However, metal complexes [M₂L](PF₆)₂ (M = Ag, Au) showed weak emission in aggregated state. Based on this fact, silver(I) tetracarbene complex [Ag₂L](PF₆)₂ has been employed as a turn-on fluorescent sensor for PA via a self-destructive reaction. This work provides novel insights into the fabrication of stimulus-responsive organometallic materials with potential applications in biological studies.