In this contribution we discuss the role of excitons in the dielectric function and in the optical properties of Mo-S-I nanowires. We make use of the “EXCITING” package, developed in Graz. The package is based on the solution of the two-particle Bethe-Salpeter equation (BSE) for the electron-hole pairs and includes the electron-hole corre-lations. We focus on the Mo6S6 nanowires despite the fact that so far only its close relative Mo6Se6 has been synthesized. Mo6S6 has no bridging anions and the dressing anions are all S atoms. 2. It has very promising, strongly anisotropic mechanical as well as electronic properties.