Cu doped Lithium silicate was synthesized by reacting the corresponding salts under acidic medium. The XRD analysis confirms the formation of mixed phase compound of (Li₄SiO₄)_1-x-(Li₂SiO₃)x. The sample heated in air with NH₄F asaflux is rich in the orthosilicate phase whereas the sample heated in vacuum is rich in the metasilicate phase. The relative contribution of these two phases was found to be altered with the change in heating atmosphere and thus affects the luminescent properties significantly. The sample rich in the Li₄SiO₄ phase shows Cu⁺ emission whereas no emission is observed in the metasilicate phase. Intense OSL (optically stimulated luminescence) was observed in the Cu doped vacuum heated sample. The sensitivity was found to be 85% of that of the commercial Alumina. Hence it can be explored further as an OSL phosphor for the dosimetric applications.