One new triheteropoly complex was synthesized containing two hetero cations Ni2+ and Co2+ in the polymolybdate anion having composition [Mo6O24] maintaining the pH at 4.5. Product obtained was white in apperance. The IR spectral analysis of the product suggest the presence of NH4 +, M=0, Mo-O, Ni-Co,Mo-O-Mo along with hydrogen bonded H20 group in the complex. The molecular weight determination of the triheteropoly complex by cryscopic method was almost in accordance with the calculated value. The thermal stability of the product was studied and it was observed that the product involved multistep decomposition as per TGA graph producing about 29.988% weight loss which was also duly supported byDTAgraph indicating large exothermic peakmaxima at 48.34ºC. On the basis of analytical, IR spectral and thermal stability data the composition of the product is assigned as (NH4 +)8 [NiCoMo6O24] 19H2O.