Abstract⎯Polycrystalline samples of undoped, terbium-doped (CdB 4 O 7 :Tb 3+ ), and manganese-doped (CdB 4 O 7 :Mn 2+ ) cadmium tetraborate have been prepared by solid-state reactions at 850°C. Using differential scanning calorimetry and X-ray diffraction, we have determined the melting point of CdB 4 O 7 (t m = 976°C) and shown that this compound melts incongruently. The observed monotonic decrease in the orthorhombic cell parameters of the doped materials indicates the formation of substitutional solid solutions (sp. gr. Pbca). The thermoluminescence intensity of the doped materials has been shown to depend on the nature and concentration of the activators and the irradiation time.