Recipe: Cocoa substitutions...Hope this is helpful

The first is from the Ghirardelli site and the second from Cook's thesaurus. I have used theunsweetened chocolate as a sub for cocoa in brownies successfully.

Ghirardelli Unsweetened Premium Cocoa and Ghirardelli Sweet Ground Chocolate and Cocoa: For each cup of Unsweetened Premium Cocoa, use 1 cup of Sweet Ground Chocolate and Cocoa and decrease the amount of sugar the recipe calls for by cup.

Cocoa Substitutes: carob powder (Most cookbooks call for carob to be substituted for cocoa measure for measure, but since carob has a milder flavor, you might want to use more. Carob powder tends to lump, so mix it into a paste first with a bit of liquid. It also burns more easily than cocoa powder, so reduce the oven temperature by 25 degrees.) OR unsweetened baking chocolate (One ounce of unsweetened baking chocolate = 3 tablespoons cocoa plus 1 tablespoon butter or oil.)