The Chi-Lites

The Chi-Lites are a Chicago-based smooth soul vocal group. During the 1970s, they racked up 11 Top 10 U.S. R&B singles, ranging from the romantic ballads "Have You Seen Her" and "Oh Girl" to protest songs like "(For God's Sake) Give More Power to the People" and "There Will Never Be Any Peace (Until God Is Seated at the Conference Table)". All of the songs featured the tenor and falsetto vocals of Eugene Record and most of the group's hits were written by Record, in collaboration with songwriters like Barbara Acklin.

http://en.wikipedia.org/wiki/Chi-Lites