[1] Diena collected Italian postage stamps especially the early classic stamps of Italy and the Italian States of the 19th century.
He was the editor of various philatelic publications, such as the Italia Filatelica, which later merged and became La Settimana del Collezionista to form Il Collezionista - Italia Filatelica.
[1] Diena served on a number of international philatelic juries over a career of forty years.
[1] Diena signed the Golden Roll of Italian Philately in 1967, signed the Roll of Distinguished Philatelists in 1977, and received the Lichtenstein Medal in 1978.
He was named to the American Philatelic Society Hall of Fame in 2001.