Transition metal dichalcogenide semiconductors TX2 (T = Mo, W; X = S, Se, Te) are attractive because of the anisotropy of their physical properties due to two-dimensional layered-type structure [1]. TX2 materials have also been extensively investigated because of the possible practical applications such as efficient electrodes in photoelectrochemical solar cells, catalysts in industrial applications and secondary batteries, and solid-state lubricants [2, 3]. The observed excitonic luminescence near-indirect band-gap in TX2 was attributed to the recombination of excitons bound on electron-attractive neutral centers, formed by halogen molecules intercalated in the van der Waals gap [4]. Recently, thickness-dependent modulation of the optical band-gap [5] and phonon frequency [6] has been observed when MoS2 thickness decreased to a single-layer (S-Mo-S). The optical band gap of bulk MoS2 expands to an indirect gap of ∼1.6 eV in double-layer MoS2 and then to a direct gap of ∼1.9 eV in single-layer MoS2 [7]. Nowadays, single-layer MoS2 has become an appealing material in the area of optoelectronic devices, being an alternative and/or complement to graphene. The first integrated circuits based on a 2D semiconductor MoS2, which are capable of operating as inverters with room-temperature voltage gain higher than 1, has been reported [8]. The single crystals of Mo1−xWxS2 solid solutions were grown by the chemical-vapour transport (CVT) method from the instant elements. The CVT was achieved using Br2 as a transport agent. The crystals had the shape of thin layer plates with a thickness from 20 to 500 μm and a surface area of 20 to 100 mm2. From X-ray photoelectron spectroscopy results, the values of the content x similar to the stoichiometry of the nominal growth Mo1−xWxS2 composition have been determined. Moreover, using an aberration corrected scanning transmission electron microscope, the Mo and W atoms show quite random distribution in a single-layered Mo1-xWxS2. In the PL spectra of the investigated solid solutions (0 < x < 1), instead the sharp intense lines attributed to the recombination of excitons bound on electron-attractive neutral centers in 2H-MoS2 and 2H-WS2, a wide band spread have been observed. It is shown that the random distribution of the transition metal ions surrounding the halogen molecules in the Mo1-xWxS2:Br2 samples leads to the inhomogeneous broadening of the excitonic part of the emission spectra. The broad-bands IR emission observed in PL spectra of the ternary solid solutions, as well as for binary compounds are ascribed to the recombination via deep centers due to the intrinsic defects (deep levels) of the layered crystals. [1] J. A. Wilson, A. D. Yoffe. Adv. Phys. 18 (1969) 193-335. [2] A. R. Beal, J. C. Knights, W. Y. Liang. J. Phys. C: Solid State. Phys. 5 (1972) 3540-3551. [3] P. G. Moses, B. Hinnemann, H. Topsøe, J. K. Nørskov, J. Catal. 248 (2007) 188-203. [4] L. Kulyuk, D. Dumchenko, E. Bucher, K. Friemelt, O. Schenker, L. Charron, E. Fortin, T. Dumouchel. Phys. Rev. B 72 (2005) 075336 (7pp.). [5] A. Splendiani, L. Sun, Y. Zhang, T. Li, J. Kim, C.-Y. Chim, G. Galli, F. Wang. Nano Lett. 10 (2010) 1271-1275. [6] C. Lee, H. Yan, L. E. Brus, T. Heinz, J. Hone, S. Ryu. ACS Nano 4 (2010) 2695-2700. [7] K. F. Mak, C. Lee, J. Hone, J. Shan, T. F. Heinz. Phys. Rev. Lett. 105 (2010) 136805 (4pp.). [8] B. Radisavljevic, M. B. Whitwick, A. Kis. ACS Nano 5 (2011) 9934-9938.