Diane Gross and Khalid Pitts, the owners of the Cork Wine Bar in Washington, are no strangers to publicity.

Shortly after they opened Cork in 2008, one prominent food critic said that the bar and restaurant was so popular that its “phone had better rest near a thick pad of paper.” In 2016, Bon Appétit raved about the selection at the bar’s sister retail store. And recently, Food and Wine named Cork one of the 19 best wine bars in the country.

But, this week, Mr. Pitts and Ms. Gross, who are married, are getting attention for something other than the wines and food they sell: On Wednesday night, the couple filed a lawsuit against President Trump and a business that bears his name.

Mr. Pitts and Ms. Gross claim that the Trump International Hotel, in the Old Post Office building in Washington, and the restaurants within enjoy an illegal advantage in the city’s restaurant market because of their association with Mr. Trump and that Cork has suffered as a result.