Preheat oven to 350F. Line 9-inch-square baking pan with foil.
Combine flour, cocoa, baking soda, and salt in medium bowl.
Melt 3/4 cup morsels in large, microwave-safe bowl on HIGH (100%) power for 1 minute; stir until smooth. Cool slightly. Stir in coffee, oil, brown sugar, granulated sugar, egg whites, and vanilla extract. Stir in flour mixture; fold in zucchini. Spread into prepared pan. Sprinkle remaining 1/4 cup morsels over top.
Bake for 30 minutes or until wooden pick inserted in center comes out slightly sticky. Cool completely in pan on wire rack. Lift brownies from pan; cut into 16 squares. Store in an airtight container.