The No. The No. 2 seed, de Minaur, an Australian, was a quarterfinalist in last year's 2020 U.S Open. She beat Kwon 7-6 (2) to improve her record to 7-2 on grass, which includes reaching the semifinals at Queen's Club last Wednesday.
De Minaur is ranked a career high 18th and seeks his fifth ATP title as well as his second season-highling finish.
Sonego, an Italian No. 27 and seeded No. 3 at the tuneup to Wimbledon, defeated Purcell 6-1 3-6, 6-1 for his fourth career ATP final, and second on grass.
Kwon and Purcell both reached the semifinals to make Eastbourne the first tournament where more than one man lost in qualifying. Lucky losers are those who make it to the main draw after a tournament's withdrawal.
Anett Kontaveit, Estonia's 2017 French Open champion, will be taking on Jelena Ostapenko (Lettonia), in the women's final.
Ostapenko defeated Elena Rybakina, 6-4, 6-1, to win her first WTA title match after winning the Luxembourg tournament in October 2019.
Kontaveit won the second set when Camila Giorgi, the 75th-ranked qualifier, stopped playing due to an injury to her left thigh. Kontaveit was 5-4 down in the first set. Giorgi defeated Aryna Sabalenka, the top-seeded qualifier in the quarterfinals.
This will be Ostapenko's ninth title at the tour-level, and she is aiming for her fourth title.
Kontaveit, who is 27th in the rankings, is currently ranked 1-6 in WTA finals. Her previous title was at a grass-court tournament held in the Netherlands in 2017.