In this paper, a first part will present the mechanical properties of the chalcohalide glass system GeS2-Ga2S3-CsCl. The hardness, Young’s modulus, shear modulus and toughness of a series of glasses (0.8 GeS2 - 0.2 Ga2S3)100-x CsClx with x = 0, 5, 10, 15 have been investigated and compared with other glasses. Two particular compositions 75 GeS2 - 15 Ga2S3 - 10 CsCl and 65 GeS2 - 20 Ga2S3 - 15 CsCl are compared with existing industrial chalcogenide glasses. In a second part, two multispectral antireflective coatings are presented. These coatings, developed for a multispectral application, enhanced the transmissions in specific bands.