Koplimets has MA degree in Photography (Estonian Academy of Arts, 2013). He is a member of the artist collective Visible Solutions LLC (together with Sigrid Viir and Taaniel Raudsepp). He has won Annual Award of the Cultural Endowment of Estonia (2012) and he has nominated for main art prize in Estonia (Köler Prize, 2013). Koplimets has participated in various exhibitions in Estonia and abroad. Recent exhibition projects include: The Riga International Biennial of Contemporary Art (Riga, 2018), There and Back Again (Kiasma, 2018) and Work it, feel it! (Kunsthalle Wien, 2017). His works are included in various collections, e.g. Museum of Contemporary Art Kiasma (Finland), Musée de l'Elysée, Switzerland, and Estonian Art Museum.
Koplimets works mainly with narrative installations and deals with topics such as crimes, conspiracy theories, fears and paranoias. In his latest projects Karel has been interested in topics such as traveling ja migration, e.g. shopping tourism, cross-border workers, changes in a concept of a job and workplace.