Q: The new magic devices will not work via bluetooth with my iMac.

I have connected the new Magic Keyboard and Magic Trackpad 2 to my 2014 iMac as instructed, using the lightening cable.  When unplugged, neither device will work.  When I go to bluetooth properties, I see that the iMac has recognized these devices as bluetooth devices, but when physically unplugged they no longer work.  Using El Capitan OS X.