Here we report for the first time, the syntheses of NbxCd1-xTe nanocrystals at diverse contents of niobium dopants using N-methylphenyldiamine assisted polyol technique for IR-diode laser applications. The rule of Nb dopant on the phase, shape and optical behavior of CdTe nanocrystals were evaluated. It was found that the Nb dopant expanded the crystal structure of CdTe without altering the cubic phase. The Nb dopant enlarged the particle sizes of CdTe from 2.5 nm to 11 nm. The Nb-dopant reduced the CdTe bandgap from 2.47 eV to 2.16 eV. The Nb-dopant increased the emission spectra by 10 times and narrowing the spectral bad widths by 4 times. The developed NbxCd1-xTe nanocrystals acquired remarkable quantum yield of 84 %. These marvel features may acquire the developed NbxCd1-xTe nanocrystals for prospective diode lasers, light emitting displays, and optical transistor applications.