The Trillian designers chose a color-coding scheme based on the underground maps used by the London Underground that uses different colors to differentiate between different lines. Prior versions used the corporate logos for each service, but these were removed to avoid copyright issues, although some skins still use the original icons. Trillian represents each service with a different-colored sphere. Contacts are not bound to their own IM service groups, and can be dragged and dropped freely. All contacts are gathered under the same contact list. Users can create multiple connections to the same service, and can also group connections under separate identities to prevent confusion. Trillian connects to multiple instant messaging services without the need of running multiple clients. Features Connection to multiple IM services Trillian 5 for Windows was released in May 2011, and Trillian 6.0 was initially released in February 2017. On August 14, 2009, Trillian 'Astra' (4.0) for Windows was released, along with its own Astra network. A previous version of the official web site even had a tribute to Douglas Adams on its front page.

The program was named after Trillian, a fictional character in The Hitchhiker's Guide to the Galaxy by Douglas Adams. Initially released July 1, 2000, as a freeware IRC client, the first commercial version (Trillian Pro 1.0) was published on September 10, 2002. Currently, Trillian supports Facebook, Google, Jabber (XMPP), and Olark. They also no longer support connecting to MySpace, or a distinct connection for Gmail, Hotmail or Yahoo! Mail although these can still be connected to via POP3 or IMAP. Trillian no longer supports Windows Live Messenger or Skype as these services have combined and Microsoft chose to discontinue Skypekit that was used for connection. It can connect to multiple IM services, such as AIM, Bonjour, Facebook Messenger, Google Talk (Hangouts), IRC, XMPP (Jabber), VZ, and Yahoo! Messenger networks as well as social networking sites, such as Facebook, Foursquare, LinkedIn, and Twitter and email services, such as POP3 and IMAP. It is currently available for Microsoft Windows, Mac OS X, Linux, Android, iOS, BlackBerry OS, and the Web.

Trillian is a proprietary multiprotocol instant messaging application created by Cerulean Studios. Windows and later, MacOS, Linux, Android, iOS, and Web app