Yes, you can, according to Apple support document HT207266 "Connect devices and displays with the Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter".
However, this is only useful for Thunderbolt networking (read Apple support document HT206909 "Networking two Mac systems directly with a Thunderbolt 3 cable requires Thunderbolt-enabled hosts") and Target Disk Mode (read Apple support document HT201462 "Use target disk mode to share files between two Mac computers").
The 2017 iMac does not support Target Display Mode (read Apple support document HT204592 "Use your iMac as a display with Target Display Mode") so you cannot use the 2017 iMac as a display for the MacBook Pro.
- Answered by Joseph V from Fort Langley
- 13 Dec 2017
- Flag as inappropriate Answer (does this work for connecting a 2015 macbook pro 13 retina to a 2017 5k imac?)