A series of luminescent tetranuclear silver(I) arylacetylides [Ag4{μ-(C⋮C)xC6H4R-p)4}(PCy3)y] (x = 1, y = 2, R = H (1), CH3 (2), OCH3 (3), C⋮CPh (5); x = 2, y = 4, R = H (4)) were synthesized by treatment of tricyclohexylphosphine (PCy3) with [Ag{(C⋮C)xC6H4R-p}]∞ in dichloromethane in the absence of light, and their spectroscopic and photophysical properties have been investigated. The X-ray structure of 1 exhibits a planar parallelogram-like Ag4 core and consists of [Ag(C⋮CPh)2] and [Ag(PCy3)] fragments with phenylacetylide σ-coordinated to silver atoms in a μ2-bonding mode (mean asymmetric Ag−C(α) distances are 2.05 and 2.33 A). For 2, 3, and 5, with different para substituents in the arylacetylide units, similar tetranuclear structures are observed. In contrast, the structure of 4 can be described as two interpenetrating tetrahedra of four silver atoms and four phenylbutadiynyl moieties forming a twisted cubane structure, with each silver atom further coordinated to a PCy3 ligand. The electronic absorp...