An ionic thermoplastic elastomer (ITPE) was prepared by melt blending zinc salts of carboxylated nitrile rubber (Zn-XNBR) and maleated high-density polyethylene (Zn-mHDPE). The synergism in physical properties of the ITPE is due to the formation of strong intermolecular ionic crosslinks, which act as a compatibilizer. Infrared studies revealed that ionic interactions are stronger in the ionomeric polyblends as compared to the neat ionomers. The ionomeric polyblend of Zn-XNBR/Zn-mHDPE shows higher physical properties than those of the corresponding nonionomeric polyblend of XNBR/mHDPE. Dynamic mechanical thermal analyses showed the occurrence of a high-temperature transition in the neat ionomers and the ionomeric polyblend, due to the relaxation of the restricted mobility region in the ionic cluster region, but it is absent in the nonionomeric polyblend. Reprocessability studies and measurements of physical properties show the thermoplastic elastomeric nature of the ionomeric polyblend.