Mac users who want a clean and simple IRC chat client should look no further than Textual, a product of Codeux Software.
In the words of the app’s own developers, Textual takes the best IRC has to offer and bundles it into one client. You can launch the app and, with little fuss, join the IRC server and channel of your choice. This makes it a great client for beginners. For IRC users who are a bit more advanced, Textual also includes scripting support for additional functionality.
With its clean look and easy-to-use interface, Textual has become one of the more popular IRC clients for the Mac. The app can be purchased from the Mac App Store for $4.99. A trial version is also available for download.