Are you going to be hard-coding the date range or will it need to be two seperate list boxes to make the date range dynamic? If you want to go "hard-coded" then you can use set analysis; otherwise you could use Alternate States.
Your sample picture looks like two different metrics for a single date range. But if you want two distinct date (or other dimensions) for two charts that you want to compare, and you are using QV 11, you can use the Alternate States feature to do this easily.
Or depending on the specific requirements, you could just opt to apply Set Analysis that refines the user's existing selections.