Abstract A novel flavonoid, quercetin 7-methyl ether-3,3′-disulfate ( 5 ), was obtained from the roots of Argyreia mollis , together with the known compounds quercetin 7-methyl ether-3-sulfate ( 4 ) and kaempferol 7-methyl ether-3-sulfate ( 2 ). Two further new flavonoid sulfates, quercetin 3,7-dimethyl ether-4′-sulfate ( 6 ) and quercetin 3′,4′,7-trimethyl ether-3-sulfate ( 8 ), were isolated from the aerial vegetative parts of Ipomoea regnellii , together with the known compound kaempferol 4′,7-dimethyl ether-3-sulfate ( 3 ). This is the first report on sulfated flavonoids in the Convolvulaceae family and, furthermore, the presence of flavonoids in A. capitata , A. mollis , I. reticulata and I. regnellii is reported for the first time.