The possibility of a romantic relationship between them is referred to as "Stefonnie" by fans.In Pilot, Bonnie meets Stefan on the first day of a new school year she was very smitten with his looks and started to realize that he was really looking at Elena.Were Good Friends, Former Enemies, Former Allies; They cared about each other, They were protective of each other, Stefan worked with Damon to bring Bonnie back from the Prison World, Bonnie blamed him along with Elena and Damon for her grandmother's death, They worked together to find and rescue Damon and Enzo from Sybil, Their friendship was severely strained being Stefan killed Bonnie's former boyfriend (while his humanity was off), Bonnie forced the Cure onto Stefan (turning him back into a human), Stefan will always feel guilty for killing Bonnie's former boyfriend.
In Our Town, Bonnie is still working with Stefan on discovering how to open the coffins. Stefan asks who it is in the picture and Bonnie states that it is her mother, Abby Bennett Wilson, and she can help them open the coffins.
In The New Deal, Stefan steals Klaus's coffins in which his family are in, and hides them.
He calls Bonnie for help and tells her about his plan, Later, Bonnie and Stefan go to one coffin, of which Bonnie dreamed about, and they notice that it won't open.
In The Ties That Bind, Stefan is angry at Bonnie for telling Elena about his plan and and about the coffins. In Bringing Out The Dead, Bonnie, Stefan and Abby are working together to open the coffin.
In Promised Land, Stefan is killed and has to pass through Bonnie to get to the other side.Their relationship is mostly a friendly one, even though it went through some tension after Sheila Bennett's death and especially after Stefan murdered Enzo St. Although they do not interact much throughout the series, they can still count on each other as allies.