Abstract: A process for preparing a polyfluorinated compound of formula Ar—R1 (I), wherein Ar—R1 (I) is an aromatic ring system wherein R1 is selected from the group consisting of SF4Cl, SF3, SF2CF3, TeF5, TeF4CF3, SeF3, IF2, SeF2CF3, and IF4, X2 is N or CR2, X3 is N or CR3, X4 is N or CR4, X5 is N or CR5, X6 is N or CR6, and the total number of nitrogen atoms in the aromatic ring system is between 0 and 3, wherein R2, R3, R4, R5 and R6 are independently selected from the group consisting of hydrogen, fluoro, chloro, bromo, nitro, trifluoromethyl, 2,2,2-trifluoroethyl, pentafluorosulfanyl, phthalimido, azido, benzyloxy, trifluoromethoxy, 2,2,2-trifluoroethoxy, methoxycarbonyl, ethoxycarbonyl, methylcarbonyl, ethylcarbonyl, acetoxy, t-butyl, phenylcarbonyl, benzylcarbonyl, 3-trifluoromethylphenyl, phenylsulfonyl, methylsulfonyl, chlorophenyl, methyldoxolonyl, methyl, isopropyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, fluoromethyl, fluoroethyl and phenyl.