Dehn earned a Guggenheim Fellowship in 1939, which allowed him to travel to the western United States and Mexico. In the early 40s, he worked as an instructor of etching and lithography at the Colorado Springs Fine Arts Center and received a citation from the U.S. treasury department for "Distinguished Service Rendered in Behalf of War Savings Program." Dehn started executing watercolors in late 1936, admitting he had "been afraid of color" in the first decades of his career. He rose to the top tier of American watercolorists in short order, seen in a feature article on his landscape watercolors in Life magazine (August, 1941) and a traveling show organized by the Museum of Modern Art, "Four American Water Colorists" (1943–44) in which eleven Dehn watercolors were joined with the works of Winslow Homer, John Singer Sargent, and Charles Burchfield. Dehn's watercolors were described to have a "homely poetry with a modern sensitiveness." Watercolor painting and casein painting represented signature second and third arms of Dehn's artistic output for the rest of his career. In 1944, Dehn met Virginia Engleman, who was working in the Associated American Artists printshop. The couple married in 1947 and enjoyed an artistic collaboration for the rest of his life. In the 1940s, Dehn began to sell more lithographs and to teach other American artists lithography techniques. In 1947 he joined the Society of American Graphic Artists, exhibiting his lithograph, Lake in Central Park, in the 32nd Annual Exhibition for $5.00. Dehn published his first book, titled Water Color Painting, in 1945. As he became more widely recognized and financially successful, he was able to travel extensively. As well as visiting and painting Key West and the southwestern region of the United States, he went to Venezuela, Cuba, Haiti, Afghanistan and other areas of the world. The wide range of subject matter found in his prints, drawings, and paintings reflects his travels. He was awarded a second Guggenheim Fellowship in 1951. In 1961, Dehn was elected as a full academician to the National Academy of Design, and in 1965 he was elected as a member of the National Institute of Arts and Letters. He visited Paris for the last time in 1967, where he worked at the Atelier Desjobert. Dehn died in New York City on May 19, 1968 after suffering a heart attack. He is remembered as a prolific artist of great range. His