The core organizers plan to reach out to a group of roughly 100 black executives, lawyers and other professionals who attended the July dinner. They have mutual friends. They meet socially in places like East Hampton, N.Y., and Kiawah Island, S.C. They attend the same charitable functions, like the annual fund-raising dinner in New York City for the NAACP Legal Defense and Educational Fund.

The group has been increasingly stepping into the national debate about race and inequality. Two years ago, it funded screenings so that 320,000 students across the country could see “Selma,” the movie about a crucial moment in civil rights history. After the police shootings of black people in Ferguson, Mo., and other cities, the group raised $1 million in 48 hours to fund a police reform initiative. And in August, it supported Kenneth C. Frazier, the chief executive of Merck and a member of the extended network, after President Trump criticized him.

“We have now entered more the ranks of corporate America with the financial wherewithal, with the thought leadership, to now engage around the issues,” said Ms. Smalls, who while growing up in South Carolina in the 1960s watched her parents help organize get-out-the-vote rallies and fight for equality in local schools.

The election last November, Ms. Smalls said, was an “inflection point.” The question now, she said, is “defining a narrative, politically, that matters to our community.”

The ranks of black senior executives remains small. In 2001, when Kenneth I. Chenault was named to the top job at American Express, just one other black chief executive was running a Fortune 500 company, Franklin D. Raines of Fannie Mae. On this year’s list, Mr. Chenault, who is preparing to step down after a 16-year tenure, was one of four.

While black business leaders have long used their money and influence, they have often worked individually behind the scenes. Still, many have proven adept at mobilizing money and support for causes dear to them.