Combine broth, lentils, onion, bay leaf, salt, allspice and pepper in a 3-quart saucepan. Bring to a boil over medium heat. Reduce heat to low, cover, and cook for 20 minutes. Add bulgur and cook until the lentils and bulgur are tender and the liquid is absorbed, 15 to 20 minutes more. Remove the pilaf from the heat, discard the bay leaf and stir in lemon juice.
Meanwhile, heat oil in a large nonstick skillet over medium heat. Add zucchini, squash, garlic and lemon zest; saute for 5 minutes. Stir in parsley and cilantro (or dill). Season with pepper. Stir into the pilaf. Serve hot.