I couldn't get the first method to work, and I know this is an old topic, but this is what I ended up doing for a solution:
=IF(ISNA(MATCH(A1,B:B,0)),"Not Matched", A1)
Basically, MATCH A1 to Column B exactly (the 0 stands for match exactly to a value in Column B). ISNA tests for #N/A response which match will return if the no match is found. Finally, if ISNA is true, write "Not Matched" to the selected cell, otherwise write the contents of the matched cell.