Match contents across spreadsheets to produce "yes" or "no"

You could do it like this:

=IF(COUNTIF('Sheet2'!$E:$E,C3)+COUNTIF('Sheet2'!$A:$A,C3),"yes","no")

Hope this helps.

Pete

Unfortunately it didn't work :/. But thanks for giving it a go! I think the issue is the "either" nature of the question.