Conditional Format a cell IF one cell is blank AND another cell contains text

I'd like to highlight a cell in Column A IF the corresponding cell in Column G is blank AND corresponding cell in Column C contains "this" OR "that". Partial text should be applied to Column C as other words are in the cell.
I have tried this formula: =AND($G1="",$C1="this",$C1="that") but it doesn't work. I think my problem is Excel is looking for specific text "this" and returns false if other words are in the cell. I thought maybe an asterisk would help but it doesn't. Thoughts? Thanks!CONDITIONAL FORMAT.png

Select A2:G8 & use this
=AND($G2="",--ISNUMBER(SEARCH("GUD",$C2))+--ISNUMBER(SEARCH("std",$C2))=1)

Hi, to both!

Another option could be:

1. Select A2:G8 leaving activecell A2
2. Use this formula into CF:

=($G2="")*(COUNTIF($C2,"*GUD*")+COUNTIF($C2,"*STD*"))

3. Apply Red Font

Blessings!

In your OP you said GUD or STD & showed rows 3,4 & 6 with no highlight, so I assumed that if col C had BOTH GUD & STD then it should not be highlighted.
This part of the formula
--ISNUMBER(SEARCH("GUD",$C2))+--ISNUMBER(SEARCH("std",$C2))
will return a 1 or a 0 for each check, so if the cell contains both values it will return 2. I therefore added the =1 to check that only 1 of the values was present.

behmen... did you try my proposed formula? this works with GUD or STD or BOTH (GUD or STD) are present. Blessings!

Ahhh, I can see how that would be confusing. I should have left the cell in Column G blank for one of those samples which had both tests and highlighted the sample # in my example.