Mark McGhee has bolstered his Aberdeen squad after wrapping up deals for Scott Vernon and Yoann Folly.
The pair are the club's fourth and fifth signings of the summer following the arrivals of Rory McArdle, Josh Magennis and Mark Howard.
Ex-Plymouth midfielder Folly has been on trial for a number of weeks and has impressed McGhee in pre-season outings.
Vernon featured for Colchester last season and has now joined after passing a medical late on Sunday night.
The 26-year-old, who has also played for Oldham and Blackpool, goes straight into Aberdeen's squad to face Port Vale on Tuesday.