CdxZn1−xS nanoparticles have been synthesized on the base of functionalized nitrile butadiene rubber (FNBR) by SILAR method and characterized by various techniques. Both binary and ternary sulfide nanocrystals have been obtained in the cubic phase with very high purity at room temperature. The average particle size decreased from 2.49 nm to 2.22 nm and then increased to 2.44 nm by the increasing of zinc concentration from 25 % to 50 % and 75 %. The calculated Young's modulus for (111), (220) and (311) planes are 97.84, 78.51 and 64.33 m2 N−1 for CdS and 95.84, 69.68, 53.42 m2 N−1 for ZnS, respectively. The band corresponding PO32− (977 cm−1) shifted to 969, 975, 972, 973, and 972 cm−1 upon the formation of CdS, ZnS, Cd0.5Zn0.5S, Cd0.75Zn0.25S and Cd0.25Zn0.75S nanoparticles into FNBR matrix, which is explained by Hooke's Law. EPR spectra of CdS/FNBR nanocomposite show broad and singlet asymmetric, isotropic symmetry (gx=gy=gz). The appearance of a new line in the 3518 G magnetic field is observed in both CdS and Cd0.5Zn0.5S compounds’ spectra.The total mass loss of the samples NBR, FNBR, Cd2+ and Zn2+ ions containing FNBR are 93.76, 59.77, 60.03 and 57.79 %, respectively. High crystallinity is caused by complete interaction of metal ions with functional groups during the nucleation.