B1A4 (Korean: 비원에이포) is a South Korean quintet boy band. Formed by WM Entertainment in 2011, they made their debut with their release Let's Fly. The band consists of Jinyoung, Baro, Sandeul, CNU and Gongchan. The group was first introduced through an online comic series, or "webtoon".

The members of B1A4 were first introduced via webtoons before their actual pictures were released.^[1] Their first EP Let's Fly was released on April 21, 2011 and includes a song written and composed by the member Jinyoung called 'Bling Girl'.^[5] On the same day, the music video for their lead single "O.K" was released. Two days later, they made their live debut on MBC's Show! Music Core.^[6] Over the week of May 1, 2011, they were a guest on Starry Night radio.^[6]
On June 22, 2011, the first episode of MTV's Match Up! was aired, featuring Block B and B1A4. The first episode revealed B1A4's music video for their follow-up promotions "Only Learned the Bad Things." The show allows both groups to show off their musical talents and unseen charms through weekly missions and behind-the-scenes footage of their daily lives as newcomers to the Korean pop scene. The program has 8 episodes in total.
Jinyoung fainted after filming for B1A4's MV 'Only Learned the Bad Things' ended. He was rushed to hospital where he was diagnosed with enteritis.
On September 16, 2011, B1A4 returned with their second EP, It B1A4 and started promoting the lead single "Beautiful Target". An MV teaser for "Beautiful Target" was leaked on their official youtube channel on September 8th, and the full MV released on September 15th. An alternate version of the MV "Beautiful Target (ZOOM ZOOM ver.)" was released on October 6th.