Find artwork you adore and put it on the walls. Perhaps a nice floor plant in the corner, and a small plant in the archway. The arch is a nice architectural feature and I'd be inclinded to leave it blank and let is speak for itself.

If it were me I would leap at the chance to put a wonderful deep-seat upholstered banquette on the wall, to not put the dining table in the center of the room. More glam than this, but the general idea:

What's the room on the other side of the arch?

Is that the front entrance? I agree to leave as is but I would try to put something interesting on the dining room wall that you would notice when looking through. Piece of furniture maybe. Do the paint colours of the two areas complement one another?

The arch is on the right as you enter from the front door. All the paint will be the same “white”. Currently we are painting the entire home SW 7001 Marshmallow. Creating a blank canvas.

I would only leave the arch if it framed something wonderul to look at. I think I'd be looking for something with more arches (and not a grid mirror). However, it doesn't look easy to stand somewhere at the entry where you'd be looking straight through the arch. If you have a very nice collection of glass or other artstic objects, you could put shelves in for display, or you might be able to hang a plant in there, but it's pretty narrow. Otherwise, before everything needs is painted, I'd close up the arch.

One very cheap "fix" would be to cover the arch by placing wall mirrors over them on both sides, or art on the dining room side, mirror on the entry side. What bothers me about the arch is the modern structure of the rest of the room and this uncomplimentary Roman empire feature. If you are super-keen on Bauhaus decor, I can see making it work with the windows.... If you like it though, you should leave it.

It looks to me like previous owners of the house were unhappy with the unusual construction of the dining room, with windows only in one corner. So they mirrored one wall and maybe created this arch? But I really like the unusual configuration, and even if I didn't go for a banquette, I go for a striking round table positioned into the corner opposite the window corner. Or an oval tulip table along the back wall might be great if you plan to keep the arch. There's loads of room for a sideboard, art, shelving .... doesn't need to be expensive to be an enjoyable and inviting space for people to enjoy being in.

“….. what to do with the arch area?”

Like Kendrah, I think the arch is a nice feature and I’d leave it. It helps with natural light in both rooms, and a sense of openness. It’s a common feature in certain areas of the country — west, southwest, south. I like her idea of having a plant sitting in it (or a lovely vase, piece of pottery, or statue), or just leaving empty.

It’s hard to say about decorating the walls and arch without knowing more of how the room will be used and what your decor style is. How big is your family? Will you be using the room for daily meals or more for formal/holidays/etc? Do you need storage such as a china cabinet or buffet? You say you’re keeping the dining set for now, what do you think about recovering the chairs?

I think the windows would look nice with curtains (meeting in the corner). Are you planning to have a rug? Have you chosen a light fixture?

ETA: Examples of curtains on windows like yours:

There are 2 of us and we eat all our meals in this room. We do like to entertain. I think a small hutch would be nice. For storage and for holiday decorations.
Thanks for the window cover ideas. We are trying to figure out what is best - we prefer modern. Most people are suggesting shutters but my husband and I aren’t fond of them for our home. I appreciate all the suggestions, it’s very helpful.

If you are considering investing in a hutch, I'd do so after you purchase your new dining room table and chairs. And, I might not go too small with the hutch. Sometimes using smaller furniture in a room actually makes the room look smaller. Of course you don't want to crowd it either...

@Jilly, I love your curtain pics. Especially the middle one.

Why did you keep the arch? I do not see any other arches . As for what to do on e thwalls that depends on many things . To start what is your style , with no clue to tat all you will get is a bunch of random pics and no help at all. I think you mean a buffet not a hutch and I agree frist the table then if you have space a buffet . Post a to scale floor plan here and we can help with size of table and shre your style we can help with the walls. Post all of that info in comments here DO NOT start another post. I hate banguette seating it barely works on a picnic bench and not at all for actual seating in a DR Try getting in and out at a dinner party in a dress so classy.

There is an arch in the bedroom and it was suggested we put an arch going from the DR to the kitchen. After reading the post my husband and I decided to leave the arch there. We like the light and how it looks from the front door and dining room.
The measurement of the dining room is 11ft x 101/2ft.
We like modern.
Truly we are starting from scratch by painting our walls SW Marshmallow - creating a blank canvas.
We have this couch in our living room which is part of the same room. We do like the couch.

I like the couch!

You should certainly keep the arch if you like it. It's hard to tell from photos what something is like if you are not in the house.

As you can see, Patricia has a lot of hates that are purely personal to her but she seems to think it is universal decorating advice. Banquette seating is glorious, which is why so many restaurant customers prefer it. Now that I know it is only you and your husband using the dining room mainly, I don't think I'd recommend banquettes here. I do love off-center dining table placement, so I would really be happy to have an excuse to put the table out of the dead center of the room (and find a creative solution for the lighting).

In saying you like '''modern''' you are going to open yourself up to hearing and seeing all kinds of styles people associate with that word. The question I'd probably ask is: "How eclectic do you intend to be, or are really look to create a single stylistic cohesion to fill in your blank slate." Either that fun and comfy looking retro-ish sofa is the jumping off point for similar decor -- not matchy matchy but all in the family -- or you like to mix it up a bit with an antique or something pop or you've always loved Frank Lloyd Wright.

Agree with complimenting the dining room with living room. Retroish - not matchy matchy.
We like a few statement pieces.
Definitely a nice large piece of art for the wall.
Appreciate your insight.

What about a tall urn in that arch?

Perhaps something you could put flowers or branches in?

i agree to keep the arch - it’s interesting! love the idea of branches suggestion -