CdS nanocrystals (NCs) with size 4.3nm, were coated with ZnS to form CdS/Zn Score shell in order to Examine the effect of lattices train due to lattice mismatch of 7%. Besides structur alanalysis, the optical absorption spectrum red-shifts with increasing ZnS shell thickness affirming core–shell nanostructure formation. Radiative lifetime of CdSNCs remains in variant upto two mono layers of ZnS on CdSNCs and reduces to half the value at three mono layers onwards. The experimental finding is indicative of strain induced change in symmetry of hole wave-functioning round state.