Copper phthalocyanine dyes, widely used in various imaging systems, are susceptible to gas fading under ambient conditions. One of the main factors responsible for such fading is the presence of ozone. Addition of suitable antiozonants has been shown to be effective in improving ozone stability. Although the exact mechanism of such stabilization is not fully understood, the electronic structures of the additives have shown significant impact on their effectiveness. In order to increase the ozone stability of copper phthalocyanine dyes without any additives, several copper phthalocyanine dyes containing substituents of varying electronic structures were synthesized and tested for ozone stability. The structure of a copper phthalocyanine dye with significantly improved stability to ozone is described in this paper. Possible mechanisms leading to such stability are also discussed.