Will Adobe Illustrator CS2 work on OS X Yosemite‎?

CS2 was written for PowerPC Macs, so shouldn't run on any OS past Snow Leopard.

You would be much better served switching to other apps, like Affinity Design (vector art) and Affinity Photo. These are available to buy on the App Store for the price of one month's Adobe subscription! They are fully 64-bit, and take advantage of the latest OS X technologies.

CS2 is ten years old. The latest version of Adobe's software is subscription only, and can be quite expensive. Furthermore, when you stop paying, the apps stop working.

Unless you're expecting to receive files from other people, then there's no great need to stay with Adobe. Lots of people are moving away, and other software companies are providing the tools to do the job.

There are a number of alternatives, but as I said, the Affinity suite (a DTP app is expected at the end of the year) seems to be the most professional replacement. (I'm not affiliated, other than a happy customer.)

You could try getting a cheap version of CS5, CS5.5 or CS6 on eBay, but make sure that you can get it authorized from Adobe's software when you install it.

5.5 and up will "work" but there are a hand-full of random bugs, especially with Illustrator. I'd tell you to post on the adobe forums but they can be a crap shoot when I use them.