We already know that Joss Whedon will be returning to write and direct the sequel to The Avengers, which he also wrote and directed, well today Marvel announced that the official release date for that sequel is May 1, 2015.
What is interesting, however, was that the sequel was specified as “untitled” meaning we won’t be seeing The Avengers 2 in 2015. It seems likely that the film with feature a subtitle in the same vein as Captain America: Winter Soldier and Thor: The Dark World