NOVELTY - Manufacture of ionic liquid involves reacting ammonium salt of sulfuric ester (I), ammonium salt of phosphate ester (II), or ammonium salt of sulfonic acid (III), and nitrogen-containing compound chosen from amine compound, imidazole compound, pyridine compound, pyrrolidine compound, pyrrole compound, pyrazine compound, pyrimidine compound, triazole compound, triazine compound, quinoline compound, isoquinoline compound, indole compound, quinoxaline compound, piperazine compound, oxazole compound, thiazole compound and morpholine compound.    USE - Manufacture of ionic liquid. Uses include but are not limited to electrolyte solution for lithium-ion secondary battery, lithium secondary battery, dye-sensitized solar cell, fuel cell and capacitor, electroplating bath, lubricating agent for bearing for motor, gas absorbent, synthesis catalyst, solubilization solvent, and solvent for high-performance liquid chromatography.    ADVANTAGE - The ionic liquid is manufactured efficiently, by simple method.    DETAILED DESCRIPTION - Manufacture of ionic liquid involves reacting ammonium salt of sulfuric ester of formula: R1-(O-A1)n-O-S(=O)2-O-.(NH4)+ (I), ammonium salt of phosphate ester of formula: R1-(O-A2)m-O-P(=O)(-O-(A3-O)q-R3)-O-.(NH4)+ (II), or ammonium salt of sulfonic acid of formula: R4-(O-A4)r-S(=O)2-O-.(NH4)+ (III), and nitrogen-containing compound chosen from amine compound, imidazole compound, pyridine compound, pyrrolidine compound, pyrrole compound, pyrazine compound, pyrimidine compound, triazole compound, triazine compound, quinoline compound, isoquinoline compound, indole compound, quinoxaline compound, piperazine compound, oxazole compound, thiazole compound and morpholine compound.    R1,R4=1-20C linear, branched or cyclic alkyl, 6-30C aryl, or 7-31C arylalkyl (all optionally substituted);    A1,A4=2-4C linear or branched alkylene;    n,m,q,r=0-50;and    R2,R3=1-20C linear, branched or cyclic alkyl, 6-30C aryl or 7-31C arylalkyl (all optionally substituted), or H.