Populate a cell based on a value being found in an array

Hi,

Thanks for reading, my brain has shut down and i need to finish this soon.

I have a list of email addresses as part of a large workbook, i need to pour through them and see if any of them are included in a smaller list. If one is found i need to populate a cell on the same row with a "Y".

so in pseudo i think its something like this

if cell1 included in array then "Y" otherwise "blank"

tried lookup, vlookup, index/match, no success, why is this killing me?

Cheers in advance
Col

It works and i cant see why! i need to sleep.

thanks bud