Franz 2.0 is a desktop app that puts messaging services altogether in one place. It can combine apps like WhatsApp, Slack, Facebook Messenger, WeChat, HipChat, Skype and a lot more. You can even use multiple accounts for the Facebook Messenger - mix your business profiles and your private ones if you need to.
WhatsApp for Desktop gives you the possibility to have all your messages in all your chats synchronized on your PC. And do not worry about security, every message is encrypted so only you and the recipient can read it, hear it or see it.