Despite the fact that it is currently full trend to shape the dining room table with uneven chairs (I think that personally, I think it is the best thing to give singularity to that space), perhaps the idea does not appeal to you too much and you are looking for ideas because you do not know what to do with those old chairs that you have inherited, or bought on the trail because they were "priceless", waiting for a "I can think of something".
If you are one of those who, like me, do not give anything for lost, at least in the field of decoration, and you find three chairs like the ones in the picture, I suggest you give new life, just as they do in 31 & Change, a company based in Brooklyn, which is dedicated to recycle waste furniture, turning it into unique pieces, personal and, above all, with a touch of humor. His interventions are absolutely handmade and the results, unexpected and surprising.
How about? Surely you are able to get a similar piece. What you have to do is remove the seats of the three chairs, sand them to correct imperfections, paint them of the same color if what you want is to unify them (although I think the result can also be spectacular painting them of different colors), separate the backrests of the seats, and look for a plank that will serve as a seat.
The result will be a single bank, which you can place both outside (a porch, a terrace), and inside: in the dining room, as a seat to barefoot next to the entrance door, etc. And the best thing about it is that it will be a unique, original furniture and, if you have done it above, for which you will feel a special satisfaction.