Dinis was an advocate for the preservation of Portuguese-American history, particularly the establishment of monuments that commemorated the accomplishments of Portuguese explorers and settlers.
The movement to honor Peter Francisco was initiated by Senator Edmund Dinis and the legislature approved a bill in 1954 making March 15 Francisco Day throughout the Commonwealth of Masaachusetts. This was the date of the Battle of Guildford Courthouse, and the day recognized Peter Francisco's heroic contribution toward the success of the American Revolution.
It is believed that Francisco was didnapped from his native Portugal and brought to the United States at the age of four. He would grow up to become a citizen; one of the most colorful soldiers in the Continental Army; a landed gentleman and businessman, and sergeant-at-arms of the Virginia House of Delegates.
Attorney Dinis also filed and secured the passage of Chapter 539 of the Acts of 1955 establishing the Dighton Rock State Park, in Dighton, Massachusetts.
In his later years, Dinis single-handedly persuaded the Bangor Historical Society and City Officials to dedicate a parcel of land by the Penobscot River to celebrate the Portuguese Estevan Gomez's 1525 landing in that area, while Gomez was in the service of Spain. The Estevan Gomez memorial monument was dedicated on Columbus day in 1999 in Bangor, Maine, on the banks of the Kenduskeag River near Penobscot.
Similar efforts resulted in the dedication of the Alvarez Fagundes Monument in Halifax, Nova Scotia, Canada, in 2000. Nova Scotia's name "Bay of Fundy" is attributed to Fagundes and older maps referred to Cape Breton as "Cabo Fagundo". Fagundes sailed around the area in the early 1500's.
Through his ownership of WJFD's Radio Globe 97.3 FM, a 50,000 watt FM radio station, Dinis took a leading role in various social, economic and political issues of concern to the Portuguese community for more than thirty-five years. WJFD's twenty-four hour broadcast in the Portuguese language made an immeasurable impact upon the significant number of Portuguese residing in the eastern New England, all because of Dinis' generosity and dedication.
In 2007, Dinis, who lived in Dartmouth, donated $150,000 to UMass Dartmouth to establish the Edmund Dinis Portuguese-American Political, Legal and Public Service Collection at the Ferreira-Mendes Portuguese-American Archives. The collection supports the study of Portuguese-Americans' political contributions to America.