One way...

format the font in C1 to Webdings, then use the following formula in
C1...

=IF(OR(A1="",B1=""),"",IF(AND(A1=B1),"a","r"))

"a" in Webdings is a tick, while "r" is a cross.

The formula results in a blank when either A1 or B1 are blank.

Ken Johnson