NOVELTY - Polybenzimidazole (PBI) based polymeric forms of ionic liquids (III) and (IV) are new.    USE - The PBI based polymeric forms of ionic liquids is useful for separating media in membrane, sorbent, extraction, chromatography, as polymer electrolytes in devices comprising fuel cell, batteries, supercapacitor, solar cell, as dispersing agents, as nanomaterials, as microwave absorbing materials in electrowetting, water breathable fabrics (claimed).    ADVANTAGE - The PBI based polymeric forms of ionic liquids have high stability, solubility coefficient, selectivity, permeability co-effficient, permselectivity and sorption capacity for gases comprising hydrogen, nitrogen, carbon dioxide, methane, helium, hydrogen sulfide and water vapor.    DETAILED DESCRIPTION - Polybenzimidazole (PBI) based polymeric forms of ionic liquids of formula (III) and (IV) are new.    R1, R2 = 1-20C alkyl, trialkyl, silyl, cyclo alkyl, aryl, arylene, alkylene or heterocyclic ring (comprising pyridine, pyrazine, furan, quinoline or thiophene) comprising straight chain, branched, cyclic or aromatic or their derivatives substituted with functional groups including halo, nitro, ether, aldehyde, ketone, OH, carboxylic, sulfonic or ester;    a, b = repeating units;    X4 = (CnH2n+1)COO, haloacetate, (CnF2n+1)COO, Ar1COO, (CnH2n+1)SO3, (CnF2n+1)SO3 or Ar1SO3;    Ar1 = optionally substituted aromatic moiety, NO3, NO2, PO3, BF4, HP04-N(SO2CF3)2, H2PO4 , HSO4, S2O3 , ClO, BrO3, , CrO4, HCO3, C2O4, MnO4, NH2, FeCl4-, PF6-, (CN)2N-, C16H34PO4-, C12H25C6H4O3-, SCN-, CH2=CHCOOCH2CH2CH2SO3-, CH2=CHSO3-, C6H4CO3SN-, o-tosylate, pyrazolium anion, imadazolium anion, triazole anion, tetrazole anion, oxazole anion, indolium anion, benzotriazole anion, phenoxide anion, N(SO2(CnF2n+1))2, diethyleneglycolmonomethylethersulfate, (CnH2n+1)SO4-,(CnF2n+1)SO4-, (B(CN)4-), tetrafluorosuccinate, hexafluoroglutarate, oxalate, malonate, glycolate, L-tartrate, maleate, mucobromate, nitrilotriacetate, 5-aminotetrazolate, DL-tartrate, lactate, gluconate, and/or DL-malate;    R = tetraamine monomer of formula (Va)-(Vf);    R11, R12, R3, R4 = H, CH3, CF3, F, Cl, Br, I, NO2 or 1-24C alkyl or aryl;    X = -CH2-, -O-, -SO2-, -C(CH3)2-, - C(CF3)2-, -C(Ph)2-, -CH3C(Ph)-, -CH3C(isopropyl)-, -CH3C(tert-butyl)-, -CH3C(n-propyl)-, -CH3C(ethyl)- or 1-24C alkyl or aryl;    R5 = dicarboxylic acid of formula (HOOC-(CkHmX1n)-COOH) (VI);    k = 1-30, containing alkyl, aryl, aromatic, arylene, alkylene, arylene-ether or heterocyclic ring comprising pyridine, pyrazine, furan, quinoline or thiophene groups as straight chain, branched, cyclic and/or aromatic;    X1 = H, O, N, S and/or halo;    n = 0-10; and    m = appropriate numbers of H.