It sounds like you might be thinking of Trent, one of the main Rangers in the show. He is the Black Dino Ranger, and is often shown to have a close relationship with the other Rangers, especially Kira, the Yellow Dino Ranger.
They share a lot of screen time and have moments of strong friendship and teamwork. However, there's no romantic relationship between them in the show.
Do you have any other questions about Dino Thunder or Power Rangers?