The ultraviolet-visible (UV-Vis) absorption spectra, optical constants (complex refractive index N=n+ik) of the thin films and thermal characterizations of three kinds of novel nickel-azo dyes based on 4-methylthiazole, benzothiazole and 6-methylbenzothiazole were investigated. Particularly, a dye based on 4-methylthiazole, with higher refractive index n=2.46 and lower extinction coefficient k=0.18 at the wavelength 650 nm and a sharp threshold of thermal decomposition at 330℃ was obtained. The results of the static optical recording test indicated that higher reflectivity contrast can be obtained at a low laser power and narrow pulse width for a single layer of the dye film based on 4-methylthiazole. These results demonstrate that the nickel-azo dye is a promising candidate as a recording medium of digital versatile disc-recordable (DVD-R).