OICC Press Iranian Journal of Catalysis 2345-4865 3 2 2024 02 03 Silica gel: A very cheap, reusable, and efficient catalyst for green preparation of some bis-4-hydroxycoumarin on water EN Saeed Khodabakhshi Department of Chemistry, Yasouj University, Yasouj, Zip Code: 75918-74831 P.O. Box 353, Iran. Mojtaba Baghernejad Young and Reasearcers Elite, Gachsaran Branch, Islamic Azad University, Gachsaran, Iran Journal Article 2024 02 03 Silica gel has been used for synthesis of biscoumarin derivatives starting from 4-hydroxycoumarin and aryl aldehydes. The reaction conditions are completely in agreement with green chemistry principles including sing water as media and a recyclable and safe catalyst. This method is also simple and inexpensive and leads to high yield of products in short reaction times.