Adobe CS3 and CS4 basically stopped working reliably or not at all once OS X 10.10 Yosemite was introduced.
Adobe CS2 stop working after OS X 10.7 Lion was introduced as CS2 is an even older Adobe CS version.
You have three options.
First,
Subscribe and update to the lastest versions of Adobe CS6.
Yes, ***, but if you absolutely rely on Adobe software, then you have no choice, but to subscribe to Adobe's subscription/"conscription" ransomware, rent-a-software model.
Second,
If you have a new iMac, you will need to purchase an external optical drive to accomplish this next option.
If you want to keep using your Adobe CS2, you can purchase virtualisation software like Parallels Desktop, VMWare Fusion or the free open sourced virtualisation software Virtual Box, then call Apple directly at 1-800-MYAPPLE and ask for sales and purchase OS X 10.6 Snow Leopard SERVER install disc ($20 U.S.D).
Once you receive this, you launch the virtualisation software, you insert the OS X 10.6 Snow Leopard server disc into the external optical and then install OS X Snow Leopard server inside of the virtualusation software.
Once installed, you can startup OS X Snow Leopard Server to boot into the OS from inside the virtualisation software.
Once OS X Snow Leopard Server is up and running, you can reinstall all of your Adobe CS2 apps from disc and run Adobe CS2 in virtualisation mode.
Third option.
Learn new tools and workflow.
Due to the passage of time and technology, there are now completely viable and cheaper alternatives to Adobe graphics software and Adobe subscription ("conscription", "ransomware") model.
In the Photoshop replacement category
Pixelmator ( a much cheaper and very close Photoshop clone that just recently and finally got some cool third party plugins!)
Serif Labs Affinity Photos (version 1.x has already MANY of the advanced feature set that current PS versions have and is a very powerful image editor)
In the Illustrator replaement category
The only direct competitor-Serif Labs Affinity Designer
An Adobe Page layout replacememt is still problematic.
Quark Xpress is ripping off its customer base, too, so this may or may not be a viable page layout replacement, either.
The only other options that I can recommend for cheaper and powerful page layout app options are.
Apple Pages
Swift Publisher
iStudio Publisher
free, open source page layout app Scribus
Good Luck!