After ending domestic promotions for Can't Stop (2014), the band concentrated on individual activities; most notably, frontman Jung Yong-hwa released his debut solo album One Fine Day (2015) in January.

The band embarked on the 2015 CNBLUE Live "Come Together" concert tour, which made stops in South Korea, China, and other countries in Asia.

Frontman Jung Yong-hwa released his debut solo studio album One Fine Day (2015) in January and embarked on an Asian tour.

Guitarist Lee Jong-hyun played the role of a lead character in KBS2's Orange Marmalade and participated on MBC's reality variety program We Got Married.

Bassist Lee Jung-shin was an MC for SBS Plus's Fashion King: Secret Box and Mnet's music chart show M Countdown.

[1] During a press conference in June for the 2015 Jung Yong-hwa Live "One Fine Day" concert in Taipei, he disclosed that, upon the completion of his solo promotions, CNBLUE was set to release an album in the second half of the year.

[3] Four days later, it was revealed that the album was titled 2gether and had a set release date of September 14, one year and seven months following Can't Stop.

[9] Often compared to American pop-rock band Maroon 5, CNBLUE has found the comparisons "honorable", but has expressed its desire to distinguish its musical color and establish a unique sound.

[10] In CNBLUE's previous albums, Jung made a conscious effort to record music in order to receive recognition for it as an idol band.

[3][15] The song begins with "warped vocals, zipping synths, and booming drum machines" before building up into the "explosive chorus", leading into its catchy hook.

[4] The artwork for the special version of 2gether was designed by Belgian artist Sammy Slabbinck, his first time working with South Korean musicians.

[25][35] That same day, CNBLUE held the "Be My Cinderella" album showcase at the AX Hall in the Gwangjang-dong neighborhood of Seoul, which was broadcast on the V app.

[47][48] The quartet were guests on KBS2's talk show You Hee-yeol's Sketchbook, where they performed "Cinderella", as well as a rearranged version of "I'm a Loner" and "Can't Stop".

Writing for Billboard magazine, columnist Jeff Benjamin felt that the similarities between CNBLUE and Maroon 5 were "more striking than ever", noting that it "may position them to be more internationally appealing than ever".

[10] In a 10asia article where three staff individually picked their favorite song from recent releases, Park Soo-jeong named "Domino" as the highlight of the album.

[19] Rating the album three and a half stars out of five, Jung Min-jae of online magazine IZM sensed that CNBLUE "adheres to its wide-ranging pop rock" in 2gether.

[20] Rating the album three stars out of five, Jung Hae-wook of News Tomato complimented the band on the mixture of electronic rock and being able to form a distinct sound between the tracks, as well as their effort to experiment in order to establish its musical identity.

[18] Music critic Kim Young-dae of Idology noted that the album exhibited "diverse genres and approaches, fitting well into the current scene as a result".

He observed that the band avoided a cliché chorus and opted for "trendy brass grooves and a fluent melody" in "Hide and Seek", and dubbed the experimentation in the composition and arrangement of "Domino" as "refreshing".

Also writing for Idology as 'Mimyo', musician Moon Yong-min noticed that the album "sets its foot between [the] uneasy cleavages" of rock, K-pop, and dance music "from the texture of the approach".

He recalled past attempts of rock band popular music, but noted that CNBLUE worked well in avoiding the "discomfort" of trying to sell records.

[70] In a mixed review, Cao Jiefeng of Malaysian newspaper Sin Chew Daily claimed that the band lacks the ability to create a "hit hook" and that it should strive to develop more "outstanding" melodies.

He pointed out that the element of rock music almost disappeared in some tracks, saying that "Drunken Night" was essentially a techno dance-pop song that sounded like a 2PM or B1A4 "side-cut".

He also applauded "Radio"; he compared it to a British band Coldplay's and Swedish producer Avicii's "A Sky Full of Stars", revering its "grand chorus" and "wild guitar solo".