Azerbaijan participated in the Eurovision Song Contest 2021 with the song "Mata Hari" written by Amy van der Wel, Josh Earl, Luuk van Beers and Tony Cornelissen. The song was performed by Efendi, who was internally selected by the Azerbaijani broadcaster İctimai Television (İTV) to represent the nation at the 2021 contest in Rotterdam, Netherlands, after she was due to compete in the 2020 contest with "Cleopatra" before the 2020 event's cancellation. Efendi's selection as the Azerbaijani Eurovision entrant was announced on 20 March 2020, while the song "Mata Hari" was presented to the public on 15 March 2021.

Croatia participated in the Eurovision Song Contest 2021 with the song "Tick-Tock" written by Branimir Mihaljević, Max Cinnamon and Tihana Buklijaš Bakić. The song was performed by Albina. The Croatian broadcaster Croatian Radiotelevision (HRT) organised the national final Dora 2021 to select the Croatian entry for the 2021 contest in Rotterdam, Netherlands. Fourteen entries competed in the national final on 13 February 2021 and "Tick-Tock" performed by Albina was selected as the winner following the combination of votes from ten regional juries and a public televote.