This article describes a highly efficient heterogeneous catalytic thiocyanation of indoles, substituted anilines (electron rich and electron deficient) and N-substituted aromatic amines in water under mild and green conditions. The reaction of substrates with KSCN in the presence of silica sulfuric acid (SSA) and silica boron sulfonic acid (SBSA) as heterogeneous catalysts and H 2 O 2 or UHP (urea hydrogen peroxide) as green oxidants produces aryl thiocyanates in short ...