Vacuum Instant Messenger version 1.2.0 has been ported to OS/2, and is available for a nominal fee. There is also an older (1/16/2011) port of version 1.0.2 available. This is a Qt4-based IM client with support for multiple accounts in one profile, and many other features. From VOICE News.
Source: OS/2 Warp News and Rumors