San Diego Comic-Con's lawsuit, which was filed Thursday in U.S. District Court in Southern California, says the use of "comic con" in Salt Lake Comic Con's name constitutes federal trademark infringement.
Utah organizers have been capitalizing on San Diego's "creativity, ingenuity and hard work" through unauthorized use of its trademarks to promote their own convention, said the complaint, which seeks damages and an injunction.
The conventions have become a pop-culture phenomenon and feature the best in movies, television shows, gaming, sci-fi/fantasy and comic books. Many attendees dress up as their favorite characters.
Salt Lake Comic Con's "actions have caused, and will continue to cause, irreparable harm to (San Diego Comic-Con) and to the public which is deceived as to the source and sponsorship of (San Diego's) goods and services," the suit said.
Salt Lake City organizers say dozens of similar conventions across the country brand their events as comic cons and they are prepared to defend themselves against the lawsuit. They refused to back down after receiving a cease-and-desist letter from San Diego organizers last month.
"We really feel like they don't have a basis for this," Salt Lake Comic Con co-founder Bryan Brandenburg told The Salt Lake Tribune. "We thought there might be some more ammunition with a formal lawsuit, but they still don't have a leg to stand on."
He thinks the Utah event's instant popularity helped prompt the action. Salt Lake Comic Con drew 72,000 people to its inaugural event last fall and 100,000 to its FanX convention in April.
"A lot of comic cons start up every year, but we're the first to have the largest (first-time) comic con in North American history in little Salt Lake City," Brandenburg told the Deseret News. "We got on their radar and we grew out of nowhere to become the third-largest comic con in our first year, so that really got a lot of attention."