I have a 2007 iMac and a newer MacBook Pro. I want to hook them together so that I can use the larger screen when I’m at home. What cord do I use to connect the two.
MacBook Pro 13", macOS 10.14
It's not possible.
Use your iMac as a display with Target Display Mode - Apple Support
You might be able to use screen sharing but it would be slow as heck and I'm not sure you can screen share to a 2007 iMac. Someone else may know.
As we are not sure what OS version is on the 2007 iMac, this is a bit of a guess but easy to do. Go to System Preferences > Sharing and see if Screen Sharing is shown as a option:
Is there are way to mirror the screens?
Screen sharing was an option.
How to connect MacBook Pro to 2007 iMac
