Next time please post actual workbook so we can test without having to recreate....

Select C2:C16 and go to Home|Condititional Format|New Rule

Select Use a formula to determine which cells to format from top

and enter formula:

=SEARCH($D$3:$D$12,C2)

click format and choose from Fill tab.

Click Ok. Click Ok to exit and apply.

Select now D3:D12 and repeat above with formula:

=SEARCH($C$2:$C$16,D3)