Hi,
Or use this if Dates and Seconds are not concerned:
=TIME(HOUR($A$1),MINUTE($A$1),0)=TIME(HOUR(C2),MINUTE(C2),0)
and this if you want to ignore Seconds only:
=AND($A$1-MOD($A$1,1)=C2-MOD(C2,1),TIME(HOUR($A$1),MINUTE($A$1),0)=TIME(HOUR(C2),MINUTE(C2),0))
Regards,