Esterification of carboxylic acid with equimolar amounts alcohol can be efficiently catalyzed by biphasic 4-(benzylamino)formoyldiphenylammonium triflate (BDPAT, 3) in good yield. The catalyst can be easily recovered without loss of activity. Esterification of carboxylic acid with equimolar amounts of alcohol can be efficiently catalyzed by biphasic 4- (benzylamino) formoyldiphenylammonium triflate (BDPAT, 3) in good yield. The catalyst can be easily recovered without loss of activity.