dim n, r as range
for each r in sheet1.range(sheet1.[c1], sheet1.[c1].end(xldown))
n = application.match(r.value, sheet2.range(sheet2.[c1], sheet2.[c1].end(xldown)),0)
if iserror(n) then
r.offset(0,1).value = false
else
r.offset(0,1).value = true
end if
next