they are related in "slight" ways...but they are not connected.
A couple I can think of:
1. When the A/C is running, the condenser will be given off heat, right around the same area as the radiator, which could make your radiator performance suffer (very slight if at all noticable).
2. Running the A/C puts extra strain on the engine to turn the compressor, which could raise engine temp (again, very very slight)