On January 9, CLC held their first solo Japan fan meeting at Tower Records in Tokyo. Eight days later, the group released their fifth Korean EP, Crystyle. It marked a revamped image for the group, with a more charismatic, hip-hop concept. The EP contains six tracks including the EDM/trap lead single Hobgoblin (도깨비), which was co-written by Seo Jae-woo, Big Sancho, Son Yeong-jin, and HyunA.
Crystyle debuted on Billboard’s World Albums chart at #6, while Hobgoblin peaked at #4 on the World Digital Song Sales chart. On May 27, the group held the first fan-meeting for their fan-club, Cheshire, 2017 Cheshire Entrance Ceremony. It took place in the Olympic Hall Muse Live in Seoul.
Seven months later, CLC released their sixth EP, Free’sm, on August 3. The album title is a mashup of the words “prism” and “free”, which describes the group’s musical and conceptual direction for this EP. The album is inspired by the 1990s girl-groups Fin.K.L and S.E.S. It consists of six tracks, including the R&B ballad lead single Where Are You? (어디야?). This was another new image for the group, contrasting with the group’s previous concept in “Hobgoblin”.
CLC released the digital single To The Sky on February 1, 2018, as a pre-release track from their upcoming EP. The group appeared with a more mature, sophisticated look with the release of their seventh extended play, Black Dress, on February 22. After that, CLC held their third-anniversary concert, Black Dress on April 1. It was a donation-based, charity concert where attendees made donations to a Diabetes Association. They held their CLC Live Show In Hong Kong 2018 – Black Dress concert at Macpherson Stadium in Hong Kong on July 20.
On 17 November, CLC was named the ambassador to the Korea Insulin Dependent Diabetes Association.
On January 30, 2019, CLC released their eighth EP, No.1, with the title track No. The song is co-produced and co-written by label-mate (G)I-DLE member Jeon So-yeon and co-written by member Ye-eun. No.1 debuted at #5 on Billboard’s World Albums Chart. On February 12, the group earned their first music show win on The Show, with the title track No.
In this comeback, CLC showcased their mature, girl-crush look with classy makeup.
On May 29, the group released Me as a digital single. The song was co-written by member Ye-eun.