 Their eldest son, Cyrus Lazelle Warner Eidlitz (1853–1921), was also an architect, designing the St. George Memorial House and founding the firm Eidlitz & McKenzie, designers of the original New York Times Building, One Times Square (1903–05).Leopold's brother Marc Eidlitz was the founder of a major construction firm, Marc Eidlitz & Son Builders N.Y.C.in New York, which built the St. Regis Hotel and many other projects.