In this work, trityl bromide (TrBr) as a new, efficient, mild and neutral catalyst was used for the synthesis of henna-based xanthenes (aryl-5H-dibenzo[b,i]xanthene- 5,7,12,14(13H)-tetraones) and bis-coumarins by in situ generation of trityl carbocation under solvent-free conditions in comparison with [ Fe3O4@SiO2@(CH2)3-Im-SO3H] Cl as an acidic and reusable catalyst for the first time.
