Thematically there are many similarities between Hughes and Brooks, but what makes her poetry different?

Both poets wrote of the lives of African Americans and were able to capture the feelings and surroundings of African American narrators. One might argue, however, that Brooks's poetry was at times more political and forceful than that of Hughes. For example, her later volume In the Mecca, published in 1968, shows the growth of her political militancy in response to living in the United States as a Black woman.
The titular poem is about a large building that occupies an entire block in an African American neighborhood of Chicago. A young African American girl in the run-down Mecca is lost, and her mother searches for her. Her mother finds the girl, Pepita, murdered, and Brooks writes of this young girl, "She never learned that black was not beloved." Brooks gives voice to a girl who lived a short time and never learned from the racist society that she was considered lesser. The poems in this volume offer a more overtly political view (one that reflected the radical politics of the 1960s) than Hughes's poems do.

While Gwendolyn Brooks, like Langston Hughes, closely examines life in poor urban black culture (as is perhaps best exemplified in her poem "We Real Cool"), Brooks far exceeds Hughes in her examination of the female experience.
In poems such as "To Be in Love," Brooks divorces the experience of being poor and black with that of being a woman, examining only what it is like to be female and in love. Her speaker describes the experience: "You are the beautiful half / Of a golden hurt. / You remember his mouth / To touch, to whisper on." Her understanding of what it means to be a woman in love is that of being part of something so beautiful that it's painful, being part of the keeping of secrets.
Brooks also examines issues of womanhood in conjunction with issues of poverty. Her treatment of abortion in "The Mother" is a perfect example of this. While there is much overlap between Brooks's and Hughes's poetry, especially in their examination of what it means to be black, Brooks diverges from and expands upon those themes in her consideration of what it means to be a woman as well.