A complex [Au(NHC)2][Au(C[triple bond, length as m-dash]N)2] double salt exhibits polymorphic crystalline structures with distinct phosphorescence and variations at AuAu distances and ligand-ligand torsion angles. This serves as a model system correlating aurophilicity and low-energy charge-transfer electronic transitions and helps to understand the thermochromism and mechanochromism of the gold(i) complexes.