How to link a dropdown list to specific phrases?

Question

I'm creating a dropdown list of names that are matching to the company. For example, this is the list:

Name	Company
Name	Corresponding
Macfee-John	Macfee
Macfee- Jane	Macfee
Aventis- Doe	Aventis
...	...

My plan is when I select the name from the dropdown list (E.g. Macfee-John), it will produce the Company name in the next coloumn.

Currently I have manually written a list of all the names and the company and used:

=IFERROR(INDEX($Y$2:$Y$N, MATCH(C2, $X$2:$X$N, 0)), "")

But, it keeps returning me a circular dependency error.

Does anyone know why this happens and what I can do to fix it ?