You need to head to Level 5, you will see a Pokeball, use the warp panel Back and Forth, the Pokeball will have the Key Card.
go to silph co. its on floor 5 then once you have it go to floor 9
The card key in Pokemon Heartgold and Soulsilver is located in the Goldenrod Underground.
The Card Key that is used to open special doors is hidden in the Silph Co building. It is on the fifth floor of the building, near the southern end of the room. However, there is a Rocket agent and a Warp Panel in your way. If you find that you need to heal your Pokemon while in the Silph Co building, keep in mind that a healing station is on the ninth floor - but you need the Card Key to access it.
if you got it from the Pokemon mansion it opens the cinabar Pokemon gym
In pikachu's snatch
Why are you playing yellow? Heart Gold and Soul Silver were just released.
You need to head to Level 5, you will see a Pokeball, use the warp panel Back and Forth, the Pokeball will have the Key Card.
It is in the Pokemon House (in the basement), left of Cinnabar Island.
The card key is required for entering the 12th floor of the Silph company to fight team rocket's leader Giovanni
you click on the doors
go to silph co. its on floor 5 then once you have it go to floor 9
The card key in Pokemon Heartgold and Soulsilver is located in the Goldenrod Underground.
Step on the warp panel then when you get to the other location simply warp back!
The Beatles' version of "Yellow Submarine" is performed in the key of D flat major.
in the bottom of the Pokemon mansion
The Card Key can be found in Silph Co on the Fifth Floor.