Just do a vlookup
if list1 is in columns 1 and 2, and say list 2 is in column 5, then this would work in column 6
=vlookup(E1,$A$1:$B$n,2,false)
n is just a placeholder because I don't know how large your range is, its just the number of rows for list1. Copy the formulas down column 6 and there you go
