성연 – In My Mind (Feat. Cuzco)
Track 03 from Single "2'nd Story..."
Release Date: 2008.11.15
성연 – 이렇게 끝인거니…
Track 02 from Single "2'nd Story..."
Release Date: 2008.11.15
성연 – 그사람… (In My Heart…)
Track 01 from Single "2'nd Story..."
Release Date: 2008.11.15
이지혜, 장석현, 딘딘 (DINDIN), 성연 – 백일기도
Track 03 from Single "아이돌보컬리그 - 걸스피릿 EPISODE 07"
Release Date: 2016.08.31
성연 – Desperado
Track 02 from Single "아이돌보컬리그 - 걸스피릿 EPISODE 09"
Release Date: 2016.09.14