A three-dimensional coordination network of [AgL(MeCN)] ∞ (L=4,5-dichloro-2-cyano-3,6-dione-1,4-cyclohexen-1-ol anion) has been synthesized and crystallographically characterized. The silver(I) atom in the title compound is coordinated by two chelating oxygen atoms from one L ligand and two nitrogen atoms from an MeCN ligand and a cyano group of another L ligand at the equatorial positions, and by one oxygen atom from the third L ligand at the apical direction, completing a distorted square pyramidal geometry. Each L ligand acts in μ 4 -mode to link three silver(I) atoms into a three-dimensional network, which shows room-temperature emission upon photoexcitation at 350 nm.