The Au(II) C^N^C pincer complex [(C^N^C)Au]2 is stable under thermal conditions but disproportionates on irradiation in solution to give an Au(I)4Au(III)4 mixed-valence aggregate with a 20-membered macrocyclic structure, consisting of four linear Au(I) C-Au-N building blocks, each of which is decorated with a square planar (C^N^C)Au(III) substituent. In the crystal, the rings are stacked to form solvent-filled channels with an internal diameter of 8.3 Å and a cross-channel AuIAuI distance of 7.7 Å
