Zeolites as inorganic highly crystalline materials possess high hydrothermal stability even at high temperatures. Due to their microporosity, they exhibit selectivity for various reactions, including cracking and isomerization [1].In order to expand the possibilities for their application, there is interest in zeolites with extremely large pores. A recent notable discovery in the field of zeolite synthesis is the extremely large-pore size above 20 A⁰ aluminosilicate zeolite, ZMQ-1, achieved directly by synthesis using a quaternary phosphonium salt [2]. It exhibits robust hydrothermal stability during calcination and template removal under atmospheric conditions.

In order to obtain suitable templates for the synthesis of large-pore zeolites, we synthesized a series of phosphorus-containing coumarin derivatives [3]. In the present study an approach for synthesis of 3,3’-biscoumarins have been presented. Two types of coumarinphosphonium salts were applied as appropriate precursors for in situ generated ylides for Wittig olefination with aromatic aldehydes or coumarin carbaldehydes. In the present study an approach for synthesis of 3,3’-biscoumarins have been presented. Two types of coumarinphosphonium salts were applied as appropriate precursors for in situ generated ylides for Wittig olefination with aromatic aldehydes or coumarin carbaldehydes. The preferred stereochemistry of the formed π-bond between the two coumarin fragments has characterized as trans (E)-configuration in the obtained compounds. Several styryl coumarins containing phosphonic substituents in the lactone ring and suitable modification groups in the benzene ring have been prepared. Initial studies on their application as templates are in progress.R.N. acknowledge the European Union—NextGenerationEU, through the National Recovery and Resilience Plan of the Republic of Bulgaria, project No BG-RRP-2.004-0008.