View Inbox and Sent Items as one?

You can create a custom search folder.  Don't specify any criteria, just select the two folder you want and uncheck "include subfolders" unless you want to include those too.

You could create a "search folder" that contains these two locations. Right-click on "Search Folders" in your Navigation Pane, then select "New Search Folder." On the dialog that opens, scroll to the bottom and select "Create a custom Search Folder." Then click the "Choose..." button that appears. Provide a meaningful name, then click the "Browse..." button. Here you can check the "Inbox" and "Sent Items" folders. Click "OK". The click "OK" again. You will be prompted to continue without entering any criteria. Click "Yes." Now you should have a new search folder under "Search Folders" that contains everything from your Inbox and your Sent Items.

As you send mail, you can move the Sent folder items to the Inbox. That will work.

What I do is move the Inbox item to its relevant folder and then move the Sent item to the same relevant folder. That keeps both emails together as I need to review them. It works very well.

.... Thinkpads_User

cor worker found solution.