OICC Press Iranian Journal of Catalysis 2345-4865 6 2 2024 02 03 Preparation, characterization and the use of sulfonic acid-functionalized phthalimide (SFP) as a highly efficient and green catalyst for the condensation of arylaldehydes with 2-naphthol EN Abdolkarim Zare Department of Chemistry, Payame Noor University, PO Box 19395-3697, Tehran, Iran 0000-0002-8210-3155 Fatemeh Reghbat Department of Chemistry, Payame Noor University, PO BOX 19395-4697, Tehran, Iran. Journal Article 2024 02 03 Phthalimide was reacted with chlorosulfonic acid to give sulfonic acid-functionalized phthalimide (SFP), which characterized by 1H NMR, 13C NMR, FT-IR, XRD (X-ray diffraction), SEM (scanning electron microscopy), EDX (energy-dispersive X-ray), mass, TG (thermogravimetry) and DTG (derivative thermal gravimetry) spectra. Afterward, its catalytic activity was examined for the condensation of arylaldehydes with 2-naphthol under solvent-free conditions to afford 14-aryl-14H-dibenzo[a,j]xanthenes. The results showed that SFP was highly efficient catalyst to promote the reaction.