WATER MILL, N.Y. — Light is a thing of ungraspable nature, sometimes a particle, sometimes a wave. And for artists of the 1960s, light became a third thing: a material. Dan Flavin began making sculptures with commercial fluorescent bulbs in 1963, and spent three decades lighting galleries, warehouses, even a church. In ’60s West Germany, artists of the Zero group produced spotlit installations of spinning discs or suspended mirrors; in France, François Morellet and his colleagues at the Groupe de Recherche d’Art Visuel staged participatory events with neons or strobe lights; and in California, James Turrell, Robert Irwin and other artists loosely grouped into a Light and Space movement crafted immersive environments illuminated with soft, even pinks and blues.

The New York artist Keith Sonnier, 77, is another pioneer — of a new, luminescent art, though where Flavin and Mr. Turrell preferred pared-down simplicity, Mr. Sonnier favors conjunctions of neon with panes of glass, found objects and technological instruments. He appeared in “When Attitudes Become Form,” Harald Szeemann’s famed 1969 exhibition of postminimal and conceptual art, as well as the epochal Documenta of 1972, and he has not stopped exhibiting since, though attention from American museums has been a few shreds thinner than for some other 1960s pioneers. Many of his most visible works of recent decades have been public commissions. (If you have ever been stuck waiting for your luggage at the Fort Lauderdale, Fla., baggage claim, you will know Mr. Sonnier’s neon curves and straightaways.)

Now Mr. Sonnier is basking in the neon glow of a season devoted to his art on the East End of Long Island. “Keith Sonnier: Until Today,” at the Parrish Art Museum here in Water Mill, is his first American museum retrospective, with more than three dozen works (all that can fit in the museum’s difficult gallery spaces and central hallway), including not just neon works but intriguing sculptures in satin, rubber and bamboo. A few minutes away in Bridgehampton, the Dan Flavin Art Institute — a permanent installation administered by the Dia Art Foundation — has been supplemented with one of Mr. Sonnier’s most significant early works, uniting light, glass, objects and video-documented performance. Both are on view until next year, long after the Hamptons social scenesters will have decamped to New York or continued to Aspen.