Try this:
=IF(A1:A10="","Y","N") enter as an array formula by pressing CTRL+SHIFT+ENTER from your keyboard.
Note: Formula will return "Y"if all the cells in the range are blank, if any one of the cellls conatain a data it will return "N"
So in case of my above data example, this formula will return N; but if you remove all the data from the range, formula will return Y
Let us know if this is fine.
Regards,
Kaushik