The first syllable of the Korean word sachungi "puberty" is pronounced the same as the Sino-Korean numeral four (sa), and accordingly the group name is sometimes shortened to BOL4.

The duo went on a temporary hiatus due to Ahn's music classes requirements in the first half of 2018.

[5][6][7] On April 2, 2020, Shofar Music announced that Woo Ji-yoon had left the duo, and Ahn Ji-young will continue to promote as BOL4 as a solo act.

[8] Jiyoung and Jiyoon were both raised in Yeongju, North Gyeongsang Province, and were classmates.

The name of their duo was built on the grounds that they wanted to make the kind of pure, honest music that can only be found in adolescence.