A　simple,　efficient　and　eco-friendly　procedure　for　the　selective　monohydrolysis　of　diethyl　2,6-dimethyl-4-aryl-4H-pyran-3,5-dicarboxylates　under　quaternary　ammonium　salt　catalysis　conditions　is　presented.　The　catalytic　activities　of　various　quaternary　ammonium　salts　were　investigated　using　different　molar　ratios　of　NaOH　and　water-organic　solvent　mixtures.　The　results　indicate　that　the　combination　of　1.0　equivalent　of　tetraethyl-ammonium　bromide　(TEAB)　with　1.2　equivalents　of　NaOH　in　a　10%　water-ethanol　media　at　40　degrees　C　displays　remarkable　selectivity　for　the　monohydrolysis　of　diethyl　2,6-dimethyl-4-aryl-4H-pyran-3,5-dicarboxylates.　The　utility　of　this　process　is　demonstrated　by　the　monohydrolysis　of　a　series　of　4-aryl-4H-pyran-3,5-dicarboxylate　esters　to　afford　the　corresponding　monoesters　in　20-80%　yields　under　the　optimized　conditions.