Isadore Avenue was named by members of the family of James Mackie and Sons, a textile machinery engineering plant and foundry. It was named after two daughters, Isabelle who was the daughter of James Mackie (The Boss as he was known in the family) and Elizabeth Louise Doreen Mackie, who was known as Doreen, the daughter of his brother Tom (who went on to become Chairman of the eponymous firm). This information was confirmed by Peter Mackie a descendent of the Mackies.
Submitted application from Messrs James Mackie & Sons Ltd., for the approval of the names – Albert Crescent, Albert Drive, Albert Avenue, Albert Road, and Albert Highway – for new streets on their property situate off Springfield Road; ... the Surveyor was instructed to request Messrs Mackie and ...to submit other names for the respective streets. (21st June 1921)
"Submitted application from Messrs. James Mackie & Sons to name a new street on their property at Springfield Road Isadore Avenue.
Resolved — That as this will be the main thoroughfare from Ballygomartin Road to Springfield Road the name “Isadore Avenue” be approved". (2nd August 1921).