In order to obtain optical materials for operation in the visible, infrared and terahertz regions with high functional properties and suitable for the manufacture of optical fibers, technologies were developed and the properties of single crystals and ceramics based on the TlBr0.46I0.54 – AgI system were studied. According to the phase diagram of the system TlBr0.46I0.54 – AgI, it is possible to synthesize single crystals with a content of up to 18 mol. % AgI in TlBr0.46I0.54, as well as two-phase ceramics with a content from 18 to 43 mol. % AgI in TlBr0.46I0.54. Two compositions of each of the material types were synthesized by the directed crystallization method: single crystals of 6 and 13 mol. % composition AgI in TlBr0.46I0.54 and optical ceramics of compositions 19 and 25 mol. % AgI in TlBr0.46I0.54. It was possible to achieve an increase in the transmission range from 0.495 to 55.0 µm and to 0.504–60.0 µm with a lower refractive index: from 2.203 to 2.363 in the wavelength range of 0.5–14.0 µm, depending on the composition, by introducing AgI into the solid solution TlBr0.46I0.54. The developed materials showed resistance to ultraviolet, as well as radiation resistance under β-irradiation with doses up to 1000 kGy.