Did Brenda and Dylan leave the show the same time in 90210?

No, Brenda and Dylan did not leave "Beverly Hills, 90210" at the same time. Brenda, played by Shannen Doherty, left the show at the end of Season 4, while Dylan, portrayed by Luke Perry, remained on the show until Season 6. Dylan's character continued to evolve and was featured in storylines even after Brenda's departure.