[2,2'-Bipyridine]-1,1'-diium tricyanomethanide {[2,2'-BPyH][C(CN)3]2} as a bifunctional nanostructured ionic liquid catalyst (0.5 mol%) was used for the synthesis of 3,4-dihydropyrano[c]chromenes (14 examples) under solvent-free condition at room temperature in high yield (82-91%) and short reaction time. In addition, the described ionic liquid catalyst was also applied for the synthesis of bis...
