Selective alkylation and arylation of the C-F bonds of polyfluoroaryl imines with Grignard reagents were discovered in the absence of metal catalysts. The aldazine-N atom as an anchoring group has a special effect on the regioselectivity of the reaction. The C═N bond addition reaction with Grignard reagents was also explored. A possible mechanism was proposed on the competition between the nucleophilic substitution and addition reaction.