Search Column In Excel For Values That Do Not Exist

Enter the below into cell B2 and extend down to B5 to display values in column A that do not exist in column C

=IF(ISERROR(VLOOKUP(A2,$C$2:$C$9,1,FALSE)),A2,"N/A")

To use whole column C instead, remove header and enter the below

=IF(ISERROR(VLOOKUP(A2,$C:$C,1,FALSE)),A2,"N/A")