A second subunit named Rainbow Blaxx, was formed in January 2014 consisting of Jaekyung, Woori, Seungah and Hyunyoung.
Their special album, RB Blaxx, was released on January 20, 2014.
The music video for the title track, "Cha Cha", was directed by Digipedi and was the fourth-most viewed K-pop music video globally in January 2014.
The music video, as well as the song's choreography, drew controversy for being "too sexual".

Rainbow's third EP, Innocent, with the  title track "Black Swan" were released on February 23, 2015.

Their fourth EP Prism and the music video for its title track "Whoo" was released on February 15, 2016.
They also held their commemorative showcase at the Yes24 Muv Hall in Seoul's Mapo-gu, which was broadcast through the Naver V App on the same day as the album release.
Rainbow held their first comeback stage with "Whoo" through SBS MTV's The Show on February 16.

On October 27, 2016, it was confirmed that Rainbow would be disbanded on November 12 as the member contracts were set to end.
A second subunit named Rainbow Blaxx, was formed in January 2014 consisting of Jaekyung, Woori, Seungah and Hyunyoung. Their special album, RB Blaxx, was released on January 20, 2014. The music video for the title track, "Cha Cha", was directed by Digipedi and was the fourth-most viewed K-pop music video globally in January 2014. The music video, as well as the song's choreography, drew controversy for being "too sexual".
Rainbow's third EP, Innocent, with the  title track "Black Swan" were released on February 23, 2015. 
Their fourth EP Prism and the music video for its title track "Whoo" was released on February 15, 2016. They also held their commemorative showcase at the Yes24 Muv Hall in Seoul's Mapo-gu, which was broadcast through the Naver V App on the same day as the album release. Rainbow held their first comeback stage with "Whoo" through SBS MTV's The Show on February 16.
On October 27, 2016, it was confirmed that Rainbow would be disbanded on November 12 as the member contracts were set to end.
Rainbow (group)