B1A4 ( 비원에이포) is originally a five-member boy group formed by WM Entertainment. The line-up consisted of leader Jinyoung, eldest CNU, power vocaist Sandeul, deep-voiced rapper Baro, and maknae Gongchan. Their group name means "Be the one, all for one" and it also signifies the fact that all four members have blood type A, whilst Baro had B. They made their official debut on April 23, 2011 with the mini album "Let's Fly."
B1A4 became known for their creative concepts and colorful music which were mostly produced by Jinyoung. Their hit songs include "Beautiful Target," "What's Happening," and "Baby I'm Sorry."
In 2018, following the group's contract expiration, Jinyoung and Baro decided not to renew their contracts and pursue acting careers elsewhere, leaving the group with three members.