If you have CDR files that you want to use in Illustrator, you would need to open them in CorelDraw and then convert it to AI format. The Ai format will then be able to open in Illustrator.

How to Open Files Created in Quattro Pro. Quattro Pro is a powerful spreadsheet program that dates back to the 1980s, when it was a rival to market leader Lotus 1-2-3. It's currently part of Corel ...