Check if Cells A2 and A3 are blank in Excel

Yes, except that since it's a method you need to specify the parentheses in C#:

if (CellsBlank())

Also, if you might want to test cells other than A2 and A3 , then you could pass them as parameters to the method.

And to check the outcome in my code I would use:
if (CellsBlank == true)
{
//run the code for when cells are blank
}
else
//run the code for when cells are NOT blank
}

Is that correct?