Citizens for Responsibility and Ethics in Washington filed a complaint Thursday with the Federal Elections Commission.
The complaint focuses on ads by the Empower Illinois Media Fund. The ads discuss Democrat Barack Obama's record on abortion, crime and sex education.
Citizens for Responsibility and Ethics says the ads were the result of illegal coordination between Keyes and Empower Illinois.
The group also argues Empower Illinois has violated rules on campaign contributions and running attack ads within 60 days of the election.
Empower Illinois denies any coordination with Keyes and says the ads are meant to educate voters, not attack a candidate.