Spark by Jive Software

Spark by Jive Software screenshots

Spark is an open source, cross-platform instant messaging client for businesses.
Main Window
Spark by Jive Software 2.6 : Main Window

Alternative downloads

Astro
3.0.15
Easy-to-use Facebook messenger for Mac.
Cisco Spark
2.0
FREE
Complete communication platform for Mac OS.
Rocket.Chat
2.15.3
FREE
Web Chat Server, developed in JavaScript.