An ecofriendly photochemical approach for the rapid and effective preparation of ultrasmall NIR-emissive gold-nanoclusters from photoirradiation of water-soluble glutathione (GSH) in the presence of HAuCl 4 is reported. The formation of gold nanoclusters with a glutathione shell (AuNCs-SG) is confirmed by optical measurements, mass spectrometry, NMR spectroscopy, and transmission electron microscopy. The AuNCs-SG exhibit good luminescence quantum yield (φ=1.1 %), long emission lifetime (1.22 μs)