Connecting old iMac to new magic mouse for use

To charge the Magic Mouse, you can use the charging cable and a USB-A to USB-C adapter to plug into your old iMac or into a USB wall charger.

To use the Magic Mouse, you need to disconnect the charging cable and connected it to your old iMac via Bluetooth.

see > If you can't connect your Magic Keyboard, Magic Mouse, or Magic Trackpad to your Mac - Apple Support

dascallie wrote:

2-battery mac wireless keyboard with NO PORTS at all--so purely wireless-I want to hook it all together.

Sorry but I'm not following. Only the mouse has to be plugged in. The keyboard can't be plugged in. Maybe den.thed is following.

Indeed it does. That's to charge the mouse. To charge it you would need a lightning to USB A cable.

Lightning to USB Cable (1 m) - Apple

Sorry what? The Magic Mouse is wireless. It requires a Bluetooth connection.

den.thed wrote:

To charge the Magic Mouse, you can use the charging cable and a USB-A to USB-C adapter to plug into your old iMac or into a USB wall charger.

Not many "old" iMacs had USB C ports.

You are looking at it backwards.

The USB-C charging cable goes into the C side of the adapter and the adapter plugs into the iMac or wall charger.

Actually I didn't know the Magic Mouse came with a cable until I just looked it up. Never bought one by itself. 😎