Have one light switch trigger another light?

[joshua_lyon (Josh, SharpTools.io Dashboard)]

Unfortunately, the SmartThings hub doesn’t support setting direct associations yet, so you’ll have to use a third-party device to setup the direct associations (eg. switch on wall triggers different device).

Alternatively, you can use a SmartApp like The Big Switch which can introduce a considerable delay and requires the SmartThings hub to be available (eg. it doesn’t work if the Internet connection gets lost).

You can pick up the Aeon Labs Minimote for ~$45 and follow the steps in the post linked below to setup direct associations:

Having trouble with virtual three way (tried using Big Switch)

Also, these are the steps I used: Associate Transmitter (LTM-5) with Switch/Module To create the three-way switching, do the following: Press the Button labeled “Associate” on the Minimote. The Blue LED should blink slowly On the switch/module to be controlled, double tap the set button. the LED will blink quickly to indicate proper Z-wave communication has occurred Double tap rocker on the Transmitter to finish the association. The Blue LED will stay on for 2 Seconds to indicate Success Repeat Step 3 for all additional auxiliary switches if multiple. Press Any button to exit Association Mode.

Coming from the Vera line of products, direct association is one of the many things I miss in the ST Hub.