2010: Debut and ''Something That Is Cheerful and Fresh''
Just under three weeks since their debut, the group followed up "Too Late" with a second single, "Bbiribbom Bberibbom". The music video for the song was recorded on October 11, 2010, and features T-ara member Ham Eun-jeong. The video, along with a second music video for ballad "Nae Simjangeul Ttwige Haneun Mar", was released on October 18. The single itself was released on October 19, and they performed "Bbiribbom Bberibbom" for the first time the next day on M! Countdown. "Bbiribbom Bberibbom" peaked at number 61 on the Gaon Chart. The group's debut mini album, Something That Is Cheerful and Fresh, was released on October 28, 2010. It features the three previously released songs and various remixes. Despite being limited to 20,000 copies, Core Contents Media announced that the album had received 50,000 pre-orders and announced increase production of albums therefore selling roughly 47,000 albums.
2011: F-ve Dolls debut, ''Charming Five Girls''
The four female members of the band along with Seo Eunkyo, were announced by Core Contents Media as a sub group called 5dolls. On February 7, 2011 5dolls has released a debut music video teaser with the title track, "Ipsul Jaguk" was produced by Brave Brothers. The music video was also directed by Cha Eun-taek. The MV also featured Jay Park. On February 16 they released the MV for "Neo Mariya" and a debut mini-album "Charming Five Dolls". F-ve Dolls released a 2nd mini-album "Time To Play" on May 11, 2011 with the lead single "Like This Or That" at that same day they also released their MV for "Like This Or That".
2012: SPEED debut, ''Hommage to Lovey-Dovey''
In early 2012 debut male sub-unit with a digital single called Hommage To Lovey-Dovey SPEED members on their debut were 5 members of the group, but the union Shin new hire Jongkook of "Superstar K3". Hommage to Lovey-Dovey contains 2 songs, and was released in tribute to the song Lovey-Dovey of the Korean female group T-ara.
2013-2014: Total divestiture of its sub-group
By the middle of 2013, a representative of Core Contents Media stated in an interview that they have no plans for Co-Ed to reform again as both of its sub-units had grown and changed their line-ups to become independent ensembles. On late 2014, the group's female sub-unit, F-ve Dolls, were disbanded thus all the original female members have departed the record label. Also all original male members have parted from the agency.
