A　new　strategy　for　the　construction　of　pertrifluoromethyl　pyridazine　derivatives　is　presented.　The　tandem　reaction　starts　from　the　condensation　of　arenediazonium　salts　with　hexafluoroacetylacetone　leading　to　the　formation　of　pertrifluoromethyl　pyridazinols,　which　readily　undergo　electrophilic　substitution　reactions　with　phenols　to　afford　benzo[5,6]chromeno[3,4-c]pyridazine　products　in　the　presence　of　concd　H2SO4.