Conditional formatting to highlight a cell where 2 dates match

Question

I'm trying to create a spreadsheet with a Gantt chart layout, and want to use conditional formatting to place a colour cell where a particular activity starts. I have the dates running across the top of the Gantt on one sheet, and the project data with dates of activities in another sheet. I'm therefore looking for a formula whereby if a date in the project data sheet matches a date running across the top of the Gantt, that cell will be coloured.

How do I do that?

Here's the Gantt sheet:

And this is the source project data sheet:

oliverscheurich · Answer

Jenbons&nbsp;=SUMPRODUCT(($A3=Tabelle2!$C$9:$C$15)*(C$2=Tabelle2!$D$9:$D$15))Maybe with this rule for conditional formatting.&nbsp;&nbsp;

jenbons · Answer

OliverScheurich&nbsp;Thank you - but I can't get that to work. I've simplified things by pulling the dates into the same sheet as below - is there a simpler formula which asks if 2 dates match between row 3 and column D, shade that cell in relation to the date of row 3?&nbsp;&nbsp;