Calcium Sulfate (CaSO4) is one of the most investigated materials used as Thermally Stimulated Luminescence Dosimeter(TLD). It has been experimentally modified with several dopants to increase/modify its Thermo- luminescent (TL) sensitivity. Mn(Manganese) doping in CaSO4 being the first to be investigated.CaSO4: Mn in spite of high sensitivity, lost its popularity due to its high fading (40–85% in the first 3days after exposures). Another potential limitation in the use of this material was its sensitivity to light. We have attempted to turn its limitation to its advantage by discovering its Opticaly Stimulated Luminescence (OSL) properties. Till now no study has been reported in this material for its OSL characteristics. This paper investigates the preliminary studies CaSO4:Mn as a new material for OSL dosimetry. Their radiation was carried out from Sr-90(beta) and Cs-137(gamma) sources. Synthesis was carried out by recrystallization method using Calcium sulphate with concentrated sulfuric acid. Formation of the compound was confirmed by the X-ray diffraction (XRD) study. In addition to the study of variation of dose (beta and gamma) on the OSL signal, effect of light induced fading, effect of excitation source, effect of power and time on stimulation signal, effect of thermal and optical annealing have also been examined and reported. The paper also explores the dependence of temperature on the OSL intensity popularly known as Thermally Assisted OSL (TA–OSL) which showed a correlation between the TL and OSL traps. Theoretical analysis of OSL curves for three excitation sources were performed in order to have a deeper understanding of the OSL phenomena. OSL response to a wide range of beta and gamma doses of CaSO4:Mn and excellent reusability confirm its suitability as an effective OSL material and exploreits potential for tremendous applications in radiation dosimetry.