Is it improper for the bride and groom to host the rehearsal dinner?
Not at all. Traditionally, the groom's parents plan and host this dinner, but that's not always a possibility for a variety of reasons. Keep in mind that the rehearsal dinner can range from a banquet-style meal at a hotel to a pizza party at your favorite restaurant. You'll be able to have the party you want if you're in charge of planning it.
See More: Rehearsals + Brunches , Rehearsal Dinner