Conditional formatting if a cell is blank and other has value

Hello,
in Column E i have specific text "tier 2" or "Tier 1" i would like to format the color column L if Column E = Tier 2 and the value in the corresponding cell in column L is blank.

example
Col E = tier 2 and Col L is blank then the cell for Col L must turn red
Col E = tier 1 and Col L is blank then stay unformatted.

any suggestions.