Mr. and Mrs. Leigh B. Block were lifelong residents of Chicago and important patrons of the city's art institutions. Leigh B. Block (1905–1987) served on the board of trustees of the Art Institute of Chicago, and was the museum's president from 1970–72. During these years, the couple played a significant role in that museum's expansion.
By the time they married in 1942, Mary Block (née Mary Lasker Foreman; 1904–1981) was vice president of the advertising company Foote, Cone and Belding, and Leigh B. Block was the vice president of Inland Steel, Chicago, a company for which he had worked since 1924. The year of their wedding, the couple purchased Self-portrait with Bandaged Ear by van Gogh (1889; private collection) and a still life by Braque (1928; private collection). The Blocks decided that no work would enter their collection unless both agreed on its artistic worth. While focused on modern European art, they also acquired Pre-Columbian and ancient Chinese works. The Blocks owned three major paintings now in the Leonard A. Lauder Cubist Collection: Picasso's The Scallop Shell: "Notre Avenir est dans l'Air" (1912), Picasso's Playing Cards, Glasses, Bottle of Rum: "Vive la France" (1914–15), and Gris's The Man at the Café (1914). All three were included in 100 European Paintings and Drawings from the Collection of Mr. and Mrs. Leigh B. Block, an exhibition that opened at the National Gallery of Art, Washington, DC (September 21–November 2, 1967) before traveling to the Los Angeles County Museum of Art and the Boston Museum of Fine Arts. The Blocks sold their Gris in 1977 and the two Picassos in the early 1980s, around the time that they founded the Mary and Leigh Block Museum at Northwestern University in Evanston, Illinois.