Combine first 4 ingredients.
Beat eggs at medium speed with an electric mixer. Gradually add granulated sugar; beat until blended. Add chocolate and oil; beat until blended. Gradually add flour mixture; beat at low speed until blended. Fold in zucchini and pecans. Pour batter into a well-greased and floured Bundt pan.
Bake at 350° for 1 hour and 15 minutes or until a wooden pick inserted in center comes out clean. Cool in pan 15 minutes. Remove from pan; cool completely on a wire rack. Sprinkle with powdered sugar before serving.