Inorganic scintillators containing heavy Thallium-(Tl) in the host lattices are the novel emerging class discovered by our research group. In this class of scintillators, we studied elpasolites, ternary lanthanide halides, ternary metal halides and Tl-based hafnium/zirconium halides. These materials were synthesized by conventional melting, rotating melt direction and sublimation techniques. The single crystals were grown by conventional and modified two zones vertical Bridgman techniques and the phases were analyzed by differential scanning calorimetry and powder X-rays diffraction analysis. The emission properties studied at room temperature under X-rays irradiation shown to have efficient intrinsic and Ce3+ or Eu2+ dopant luminescence, mostly in the 370-530 nm range i.e compatible with the spectral sensitivity response of modern photosensors. The scintillation properties studied under γ-rays and α-particles irradiation shown to have good energy resolution, high light yield, faster timing response and good pulse shape discrimination. The heavy Tl ion give rise to high effective number and moderate densities to these scintillators, make them efficient for the detection of X- and γ-rays. With the modification of crystal growth furnaces, materials synthesis techniques, and purification procedure the scintillation performance of these scintillators improved significantly. The discovery and development for new Tl-based efficient scintillators and improvement in scintillation performance of the already discovered Tl-based scintillators are under investigation and will be reported in our future work.