Abstract: Process for producing isochromans having the structure: ##SPC1##Wherein R.sub.1 and R.sub.2 are each (i) separately selected from the group consisting of hydrogen, lower alkoxyl, lower alkyl, and, (ii) taken together, selected from the group consisting of benzo, cyclopentano, cyclohexano, naphtho, monoalkyl cyclopentano, polyalkyl cyclopentano, monoalkyl cyclohexano and polyalkyl cyclohexano, and R.sub.3 and R.sub.4 are the same or different and are selected from the group consisting of hydrogen and lower alkyl comprising the steps of intimately admixing:A. an alkanol having the structure: ##SPC2##B. an acetal having the structure: ##EQU1## (wherein R.sub.5 and R.sub.6 are each 2-propyl); C. a protonic acid selected from the group consisting of p-toluene sulfonic acid and phosphoric acid; andD.