Connecting new laptop to iMac
Looking to buy either new mac air or mac pro. Can i connect any of these laptops to my old iMac 21.5 inch, late 2013, to use it as an external monitor? Thank you
iMac 21.5″, macOS 10.15
No Mac from 2020 and later can be connected to an iMac as a display.
From 2019 and earlier and running Catalina and earlier, and to certain iMac models (including this one) running High Sierra and earlier, yes. (Based on your footer shown here, you’ll have to wipe and re-install High Sierra.)
Tap or click for details > Use your iMac as a display with target display mode - Apple Support
And I’m here assuming you’re looking at a MacBook Pro and not a Mac Pro; those are two very different Macs.