BOL4 originally started as an indie group formed by current member An JiYeong and her high school friends. The group of four friends competed on Mnet's audition show "Super Star K 6" (2014), and in 2016,
An and fellow member Woo Ji-yun officially debuted as a pop duo. BOL4 is known for its signature breezy tunes, which include hits "Galaxy" (2016), "Some" (2017), "Travel" (2018) and "Stars over me" (2019).
After Woo Ji-yun left the group in 2020, BOL4 has been a one-person-band of An, dropping "Leo" (2020) featuring Baekhyun of Exo, "Seoul" (2022) and more.
Woo Ji-yun changed her stage name to Odd Child.