I got this question recently:
“Can you tell me if I need a permission to use songs in my script? I would like to use a song while opening credits are shown and another song of the same artist in the end of the movie. Do I need to contact her to get her permission to do so?”
You do NOT need permission to “use” any particular song in a screenplay. You’re screenplay is just a blueprint for a film, it’s not a completed film, so you won’t get in any legal trouble for mentioning a specific song.
When the film is made the producers will have to get the rights from the artist to use that song in the completed film (assuming they plan to distribute and make money from the completed film). On a side note, I’ve actually seem many films with what’s called a “scratch track” where the filmmakers used what ever music they wanted in their films and started screening the films at festivals and for industry people while the “real” music was still being figured out. In fact if my memory is correct a film I saw at the Sundance Film festival was one of them, so a film can get pretty far along without having to secure any music rights.
However, it’s generally considered bad form to list a specific song in a screenplay. As the screenwriter the main thing to consider is whether or not that specific song is needed to move the story forward. It’s a lot like including lots of camera direction in your screenplay, don’t do it, leave that to the director. There are times when a very specific camera direction is needed to keep the story moving, and you could probably think of some examples where a specific song is needed for the story, too, but these should be rare exceptions.
From the description that you gave in your question, it does not sound to me like the songs are mandatory to move the story forward so I would NOT list them specifically in your screenplay. Instead of listing a specific song it would be much better to write something like, “Over credits we hear soulful blues.”