In 1985, Rosenkranz founded the Rosenkranz Foundation with the mission of encouraging fresh perspectives and innovation in public policy, higher education and the arts. One initiative of the foundation is the monthly debate series, Intelligence Squared, brought to New York City in 2006. A live event in New York, Intelligence Squared is broadcast nationally by National Public Radio and televised by WNET Public Media/Thirteen. In late 2009, Yale University dedicated its new building, Rosenkranz Hall, in recognition of Rosenkranz's philanthropic work. Rosenkranz Hall is home to Yale's social sciences and international studies departments. In April 2010, Rosenkranz was honored by the Manhattan Institute with their annual Alexander Hamilton Award, which he received in recognition of his founding of the Intelligence Squared U.S. debate series. The Rosenkranz Foundation also endowed Yale's Rosenkranz Writer-in-Residence program, funded several exhibitions at the Guggenheim Museum and promoted Chinese art by sponsoring a major exhibit on Mu Xin donating a large collection to Harvard University, and funded a book series on modern Chinese art by Yale University Press.
Rosenkranz founded Intelligence Squared U.S. in 2006, a live debate series with the goal of raising the level of public discourse and promoting a realization that, on contentious issues, those who challenge the conventional wisdom have intellectually respectable and often persuasive viewpoints. Through an annual series of between 10 and 12 live Oxford-style debates, IQ2US brings together thought-leaders and audiences together around public policy and cultural issues. The program has been the subject of articles in The New York Times, The New Yorker, and many other publications. Moderated by ABC’s John Donvan and produced by Emmy-award winner Dana Wolfe, panelists have included Arianna Huffington, P. J. O'Rourke, Karl Rove, David Brooks, Mort Zuckerman, Wesley Clark, Bernard-Henri Lévy and many others.
Rosenkranz writes about public policy and finance for the Huffington Post, and The Wall Street Journal. He is also an investment contributor to Forbes.
Affair and lawsuit
In 2014 Rosenkranz was sued by a former mistress, Ekaterine Petuhova, who claimed he had attempted to "buy her silence" over a four year period. The relationship had ended earlier when Petuhova confronted Rosenkranz at a restaurant while he was dining with another woman. Her case was dismissed by a Manhattan Superior Court judge.