A United Brands unit filed suit against Coca-Cola.

Vernors Inc., maker of the nation’s oldest soft drink, said it has sued Coca-Cola for alleged trademark infringement for using the slogan “It’s One of a Kind” in advertising Diet Coke. Robert M. Worden, president of Detroit-based Vernors, said the firm has used the slogan “The One of a Kind Soft Drink” in advertising its products since July, 1983. Vernors’ use of the “One of a Kind” slogan predated Atlanta-based Coca-Cola’s use of the phrase by 17 months, Vernors alleged in a lawsuit filed in April in U.S. District Court in Detroit.