In this study, two recently reported 1,4-diazabicyclo[2.2.2] octane (DABCO)-based ionic liquids were used for the acceleration of the N-formylation of primary and secondary amines with formic acid under solvent-free conditions. These reagents have also been used for the efficient synthesis of N, N'-diaryl formamidines through reaction of triethyl orthoformate with primary aryl amines. These methods offer several advantages such as excellent yields, short reaction times and simple workup with the environmentally friendly procedure.