Warren Arthur, architect, lighting designer, entrepreneur and Ridgefield resident for 43 years, died on Jan. 29, at his winter home in Palm Beach, Fla. The cause of death was complications from a fall last year. He was 76 years old and the husband of Mai Tsao Arthur.

Mr. Arthur was born March 31, 1937, and raised in New York City where he attended East Chester Academy. He received his bachelor of arts degree from Brown University and his master of architecture degree in 1963 from the Graduate School of Architecture, Planning and Preservation at Columbia University. Before starting his own practice, he worked in New York City for the engineering-architectural firm T A M S on a resort project at Little Dix Bay in the British Virgin Islands.

He moved to Connecticut in 1965 to work for Eero Saarinen in New Haven. He also worked for other prominent Connecticut architects in New Canaan, including Victor Christ-Janer, John Johansen, and Hugh Smallen. His approach to architectural problems already revealed a deeper, principled search for the fundamentals of modern design.

Mr. Arthur, his wife Mai, and a third architect, John Gardner, founded TSAO Designs, Inc. in New Canaan in 1966. Starting as a small boutique offering original designs in lighting fixtures and hand-printed textile accessories, TSAO Designs quickly grew into a Main Street shop with its own production facilities. Within a decade, the business had expanded into a complex of design studio, factory, and warehouse on New Canaan’s Grove Street.

By the 1980s, the Arthurs’ firm was designing lighting systems for numerous architectural firms including Roche-Dinkeloo and for corporate clients such as Union Carbide in Danbury; General Foods in White Plains, N.Y.; Conoco Oil in Houston; and Cummins Engine in Columbus, Ind. During this period, both Arthurs traveled back and forth to Rome to work as interior design consultants to the architectural firm Brown & Deltas Associates for a project for a new city in Saudi Arabia.

By the 1990s, TSAO Designs was working with major design firms and producing lighting fixtures, and systems for clients such as the Metropolitan Museum of Art and IBM. And by the turn of the 21st century, their client base for lighting systems also included academic libraries at Harvard, Yale, Princeton, Columbia, and Rutgers Universities, and at Vassar College.

Mr. Arthur’s architectural commissions included several houses for the late Robert Sweet, the Four Seasons Racquet Club in Wilton, and a cluster of simple and austerely rich modern houses on one of Ridgefield’s lakes. His signal work of architecture is a complete redesign and reconstruction of a large house by a waterfall in New Canaan. In all of his house designs, Mr. Arthur oversaw the day-to-day construction operations, frequently contributing his own hand labor in various critical finishing operations.

A friend of the family said Mr. Arthur was loved and admired by clients, colleagues, and friends alike, both for his wry humor and gentle nature, and for the simplicity, functionality, and elegance of his designs, which expanded and humanized to a significant degree the modernist idiom.

In addition to his wife, Mr. Arthur is survived by two nieces and their children. Burial will be private. A celebration of his life will be held in the Spring.