Thin films of CdSxSe1-x (0 <= x <= 1) are prepared by simple thermal evaporation technique using CdS-CdSe nanocomposite powder. Though the starting powder had been a nanocomposite, the structural and optical properties of the films confirm that these are ternary alloys CdSxSe1-x. Systematic shifts in position of diffraction peaks in X-ray diffraction pattern and absorption edge in transmission spectra is observed as the concentration of S and Se atoms changes in the films. A plot of (alpha hv)(2) vs hv exhibit two linear regions for films containing Se atoms corresponding to two direct transitions; (Gamma(v)(8) -> Gamma(c)(6)) and (Gamma(v)(7) -> Gamma(c)(6)) due to spin orbit (SO) splitting of the valence band. The SO splitting decreases with decrease in Se concentration in the films. Raman measurements on the ternary alloys exhibit two phonon modes corresponding to CdS and CdSe LO vibration, with a small shift in peak position with composition. In addition, signature of disorder induced zone edge phonons are also observed in all the films containing S atoms. (C) 2015 Elsevier B.V. All rights reserved.