What about Terminator 2? The T-1 had to off himself, and was as much a main character as anyone.
Silent Running
Depending on whom you consider to be the main character: The Heart is a Lonely Hunter.
And if self-sacrificial death counts, The Boys in Company C.
There’s a suicide in The Last of the Mohicans but not the main character.
Dead Poets Society
And in a way, Donnie Darko.
Yes. Donnie Darko is definitely a suicide.
Keanu’s character in The Devil’s Advocate.
Just remembered Lon Chaney in The Ace of Hearts from 1921. Probably one of the earliest cinematic depictions of a suicide bomber.
The last Death Wish movie (#5?) ends with Bronson committing suicide-by-cop.
On the Beach
Oh, and here’s a shocker: The Virgin Suicides.
Butch Cassidy and the Sundance Kid
Although you get the impression that they thought they had a chance.
The Shootist, sorta.
The Butterfly Effect
The End, if attempted suicides count.
Only in the Director’s Cut, though.
Really? That must be the one I saw then. I didn’t see it in the theater.
The theater release ends with Evan going back to a (birthday?) party where he meets Kayleigh for the first time. The three-year-old Evan scares Kayleigh into avoiding him like the plague, thus ensuring all the problems resulting from her wanting to be near him never happen. Evan then burns all his journals; the final scene has adult Evan and Kayleigh crossing paths in Manhattan.
If you stretch the rules of ‘suicide’ slightly, the original British ending of The Descent
has the main character awakening from her imagined ‘escape’ from the cave, only to realize that she’s still trapped and the crawlers (evil monsters) are headed for her. She makes no further attempts to escape, but merely sits still and hallucinates her daughter blowing out the candles on her birthday cake as the crawlers close in on her.
It’s a bit of a stretch, but Spock in Wrath of Khan.
There was Vesper in Casino Royale.
Isn’t this thread about the main character?
James Bond did not commit suicide.