The national pokedex.
you cant find a porygon ,you can find it in Pokemon pearl or on platinum
Go to the Trophy Garden which is in the Pokemon Mansion. porygon is rare in Pokemon Diamond, so using the Poke Radar would be easier.
you can catch a porygon in Pokemon diamond by going to the old man in the mansion and out to the trophy garden. You also need the national dex to catch a porygon . walk around the grass and in a little while it will appear.
Porygon
you have to go to where the trophy garden is.
You use it on a porygon and it will evolve.(Pokemon Diamond, Platinum, and Pearl only.
in a science lab from a scientist i think
porygon 2 evolves to porygon z i think, I'm not sure
it is one of the daily Pokemon in trophy garden
To catch Porygon in Pokemon Diamond you need the National Pokedex. After getting the National Pokedex go to Trophy Garden in Route 212 and talk to the owner. When he says he has seen a Porygon it will now appear in the Trophy Garden.
You can obtain porygon at the pokemon mansion go to mr.backlots room answer yes to both questions and he will tell you a pokemon ran up to him and gave him a smooch on the cheek that pokemon might be porygon check every day good luck!
There's no password to get a Porygon in Pokemon Black. You'll need to trade from Pokemon White.