Title Microwave assisted synthesis of hydroxychromenes using imidazole-functionalized silica nanoparticles as a catalyst under solvent-free conditions Type of Research Article Keywords Hydroxychromene, Microwave-assisted, Heterogeneous catalysis, Salicylaldehyde, Solvent-free conditions Abstract A microwave-assisted reaction of various salicylaldehydes with dialkyl acetylenedicarboxylates mediated by imidazole-functionalized silica nanoparticles is successfully and rapidly achieved to afford the corresponding hydroxychromenes in high to excellent yields under solvent-free conditions. Researchers Hassan Valizadeh (First Researcher)، Leila Dinparast (Second Researcher)، Saideh Nourshargh (Third Researcher)، Majid Mamhad Heravi (Fourth Researcher)