AFC Wimbledon have signed Brentford defender Chris Bush and Grimsby striker Charles Ademeno.
The Dons and Brentford have "reached an undisclosed agreement" for Bush, 19, who had a loan spell at Kingsmeadow last term and rejected a new Bees deal.
Former Crawley striker Ademeno, 22, was allowed to leave the Mariners on a free after one season at the club, where he scored two goals in 12 games.
Seb Brown, James Mulley and Ryan Jackson have signed new Dons deals.
Goalkeeper Brown, 21, has played for his boyhood club since 2009 and helped them win promotion to the Football League this summer.
Utility man Mulley, 22, joined the Dons on non-contract terms in January and went on to make 24 appearances, while defender Jackson, 20, made 39 appearances last season.