The founder of the influential Ploughshares Fund dedicated to the prevention of nuclear, biological and chemical weapons was suffering from a bone infection and pneumonia at the time of her death, the Washington Post reports.
In 1970, Lilienthal founded the northern California chapter of the NAACP Legal Defense and Education Fund with her late husband, Philip.
She served on the regional board of the ACLU and was vice president of Amnesty International when the group won the Nobel Peace Prize in 1977.
The United Nations Association honored her with its Eleanor Roosevelt Humanitarian award in 1990.
Lilienthal established the Ploughshares Fund at the height of the Cold War in 1981 and it grew to be the largest U.S. grant-making foundation, focusing exclusively on peace and security issues.
She is survived by five children from her first marriage, two stepdaughters and 11 grandchildren.