Highlight Unlike Cells (Conditional Format)?

Hello I was wondering if anybody knows how to highlight unlike cells when comparing data. I have check numbers that I would like to be highlighted if they have cleared the bank. I am dropping the checks that cleared next to all checks written and trying to have the ones in transit highlighted. They are on different rows and this is what is causing the most problems.
Thank you all for your time

Thanks for your time, but what I am trying to do is highlight the cells in column A of your example if there is not a corresponding check number in column B. This way I can look and see which checks numbers have not cleared versus this showing which have cleared.
Thanks again for the time though

Is the attached what you're looking for?

Cells A1:A16 have a conditional format applied to them, if they don't have a match in
column B then the condition evaluates to True then they turn red.