The development of an efficient alternative to the widely employed Balz-Schiemann deaminative fluorination method (i. e. without using aryl diazonium tetrafluoroborate salt) is a challenging task. Herein, we report a convenient one-pot method for the FeCl3-nanocellullose mediated mechanochemical synthesis of fluoroarenes through the selective substitution of an aromatic amino group by fluorine group using pyrylium tetrafluoroborate (Pyry-BF4) and sodium fluoride (NaF) via in situ formation of pyridinium salt intermediate. The scope of the present protocol includes synthesis of thirty-four organofluorine compounds with excellent yields via a selective substitution (SNAr) of an amino group by fluorine. The presented concise methodology opens a pathway to access new chemical spaces for the late-stage functionalization in pharmaceutical industries.