Simple formula to return true if cell contains no data

I've had a brain absence and can't seem to remember how to make a simple formula to return 'true' if a cell contains no text. The ISTEXT() formula is an inverse of what I need. I'm doing a conditional formatting on a group of text. If another cell is blank, I want to format the text a certain way. If it has text in it, then I'd like to leave the cell untouched. What's the best formula?

Originally Posted by edvwvw

=not(istext(a1))

lol how dumb do I look!