DIA (short for DIAMOND and backronym for Do It Amazing) is a girl group formed by MBK Entertainment. Initially, the group consisted of Eunice, Huihyeon, Yebin, Chaeyeon, Eunjin, and Jenny, with Seunghee joining shortly before their debut. DIA made their official debut on September 14, 2015, with the lead single "Somehow" from their debut album "Do It Amazing." Over the years, the group has seen several lineup changes due to various reasons, including contract expirations and health issues, though the current members include Eunice, Jueun, Huihyeon, Yebin, Chaeyeon, and Eunchae.
In early 2015, MBK Entertainment announced plans to debut a new girl group through a reality survival program named "T-ara's Little Sister Girl Group," but this idea was later scrapped. Instead, members were selected internally, and the final lineup was revealed in June. The group officially debuted in September 2015 with the release of their album "Do It Amazing." The initial members were Eunice, Huihyeon (originally known as Cathy), Jenny, Yebin, Eunjin, and Chaeyeon. Seunghee was added before their debut but left the group in April 2016 to pursue an acting career.
In 2016, DIA introduced a new member, Eunchae, and released their first mini-album Happy Ending followed by another mini-album titled Spell, which featured a Harry Potter theme. They also formed two subgroups: BinChaenHyunSeuS and L.U.B, allowing for separate releases. In 2017, the group expanded with the addition of Jueun and Somyi, releasing their second studio album YOLO and later their third mini-album Love Generation, which was followed by a repackaged edition titled Present.
The year 2018 saw the departure of Eunjin due to health reasons, and the group's return with their fourth EP, Summer Ade, in August. This album included the track "Woo Woo," which earned them their first music show win on SBS MTV's The Show. However, by July 2019, Jenny had also left the group due to health issues. DIA continued as a six-member group and released their fifth EP Newtro in March 2019.
In 2020, DIA announced their sixth EP, Flower 4 Seasons, marking their first release under PocketDol Studio. This comeback was notable as the group promoted without members Chaeyeon and Somyi. Unfortunately, plans for another comeback in January 2021 did not materialize. In January 2022, Somyi left the group after terminating her contract. Later that year, DIA announced the release of their final album before their contracts ended in September.
On September 6, 2022, it was confirmed that DIA would release their final single "Rooting for You" on September 14, coinciding with their 7th anniversary. Despite the contract expirations, Yebin emphasized that DIA would not disband. The group officially remains on hiatus as members pursue individual activities under different labels, with plans to reunite and release music together in the future.