A series of dicationic ionic liquids (ILs) including PF 6 (PYR)C 4 (MIM)Cl, PF 6 (PYR)C 4 (PYR)Cl, PF 6 (PYR)C 5 (MIM)Cl, and PF 6 (PYR)C 5 (PYR)Cl, and monocationic ILs including (PYR)C 4 ClPF 6 , (PYR)C 5 ClPF 6 , (MIM)C 2 COOHPF 6 and (PYR)C 2 COOHPF 6 were synthesized. Their thermal stability and melting points were determined. Their solubility with organic solvents and the miscibility with water were investigated. These functional ILs are hydrophilic at high temperatures and they are hydrophobic at low temperatures, which enable the effective isolation of the resulting reducing sugar. High yields of reducing sugar were obtained for corn stalk after 8 h (20.73%) and potato starch after 6 h (72.50%) by the treatment with the mixture of PF 6 (PYR)C 4 (PYR)Cl and (PYR)C 2 COOHPF 6 . The reuse of dicationic and monocationic ILs was successfully performed and no significant reduction in yields of reducing sugar was observed. These functional ILs have important implications in the design of homogeneous and heterogeneous systems with water and organic solvents, which could be used to satisfy some specific applications. A series of dicationic and monocationic ionic liquids (ILs) were synthesized and investigated and it was found that these functional ILs have important implications in the design of homogeneous and heterogeneous systems.