The arylxenonium cation in the salt [C6F5Xe]+ [AsF6]- is isoelectronic to C6F5I, but coordinatively unsaturated with respect to N-bases like MeCN and pyridines. Co-ordination of strongly basic pyridines causes weakening of the Xe-C bond and C6F1 radical formation. The thermal decomposition of pyridine co-ordinated arylxenonium cations gives three groups of products: C-pentafluorophenylated pyridines, N-pentafluorophenylated pyridinium and N-protonated pyridinium salts. The co-ordination ability of the different pyridines shows a good correlation (C6F5 group) with the 19F NMR shift values of the p-F atom and the coupling constants 3J (19F-129Xe). An X-ray structure analysis was performed for the co-ordination product [C6F5Xe · 2,6-C5H3F2N ]+ [AsF6]- and for [C6F5-C5H5N]+ [(C6F5)2BF2]-, which was obtained by thermolysis of the corresponding adduct.