One-pot multicomponent green LED photoinduced synthesis of chromeno[4,3-b]chromenes catalyzed by a new nanophotocatalyst histaminium tetrachlorozincate
(His.)ZnCl4 nanocatalyst is realized for the preparation of chromenes with a green LED. ˙O2−, OH˙ and h+ are reactive species for this reaction. Complementary tests assured good stability and reusability of the nanophotocatalyst.