A series of aza-crown ether ionic liquids supported on magnetic Fe₃O₄@SiO₂ core–shell particles were designed, synthesized and characterized by elemental analysis, TEM, TG and FT-IR. These new aza-crown ether complex cation ionic liquids were utilized as heterogeneous acidic catalysts in Friedel–Crafts alkylation and Hantzsch reaction in good yields under convenient reaction conditions. Moreover, these magnetic particle supported IL catalysts could be readily recovered by an external magnet and reused five times without obvious loss of activity.