Unprecedented highly efficient photoluminescence in a phosphorescent Ag(I) coordination polymer.

A luminescent three-dimensional coordination polymer (CP) of [Cd II (pmd){Ag I (CN) 2 } 2 ] (1; pmd = pyrimidine) comprising two different coordination modes of Ag + ions was synthesised herein. 1 exhibited thermochromic luminescence, accompanied by positive thermal elongation of the Ag⋯Ag distance. Moreover, 1 showed a bright phosphorescence with the highest photoluminescence quantum yield ( Φ em ), approximately 60% at room temperature, among previously reported phosphorescent Ag-based CPs or metal-organic frameworks.