Single-phase La_(2–x)Nd_xMo_2O_9(0≤x≤1.8) compounds were prepared using solid-state reaction technique. Their structural and thermal p roperties were characterized by room and high temperatures X-ray diffraction(XRD), thermo gravimetric analysis-differential scanningcalorimetry(TG-DSC), and high temperature Raman spectra. The transport properties were investigated using D.C. four-probe technique and Hebb-Wagner polarization method. The substitution limit of Nb~(3+) in La_(2–x)Nd_xMo_2O_9 was determined to be in the range of 1.8