Two new fluorinated benzo [c] xanthene dyes were synthesized by reaction of fluorinated 1, 6-dihydroxynaphthalenes with 2, 4-(and 2, 5)-dicarboxy-3′-dimethylamino-2′- hydroxybenzophenone. The two critical fluorinated 1, 6-dihydroxynaphthalene intermediates were prepared via a regioselective route. The fluorinated benzo [c] xanthene dyes exhibit desired lower pKa values (6.4 and 7.2, respectively) than their parent compound (pKa= ...