Part of what gives a home its' charm and personality is new things being added over time so no, the chairs don't need to match. The new chair should 'work' with the rest of the furniture so it looks like it belongs. Think of mixing and matching your clothes and what goes together. It's basically the same idea.

Please add a photo of your sofa and chair or describe the colours and fabric etc. Found this photo on houzz, the description reads:

The pleasing blend of buttermilk, peppermint and coral colors weave in a considerable mix of patterns, but there’s harmony in the united colors. The green of the far sofa is picked up in the pillows of its neighbor, while the coral of the armchair is echoed in the subtle print on the larger sofa.

I think it also works because there is symmetry in the bookshelves and the rest of the room is quiet. It would be very nice to spend some time in this room.

You could look at pictures on Houzz to see if you can find a similar chair to yours and see what it is being paired up with it. Chairs certainly don't have to match, but keep in mind how they will be situated as well, as that will make a difference with the type of chair that you could add.

Pieces that look like they have been collected over time add interest to any interior space. The placement of the chairs, size, and other furnishings will be the deciding factor. Pick your favorite of the 2 and create a vignette, you may love it. I say play with it, ask for more help if needed.

in my view the best combinations have similarly greyed or clear colors and seat heights match.

Thank you all so much for your advise! I'm so glad no one thinks I need to match chairs because it would be rather difficult. I'm pretty good with color but not sure about heights, widths, styles and materials. Here is a picture of a similar chair and the fabric I did it in. Couch is brown, curved arms with show wood.

ops, Ok, here is the fabric.

If you have the room, I prefer a chair with arms, not a slipper chair. I love the shape of the armchair in the 1st photo and both chairs in the last photo. You could go with a solid colour but with texture or a stripe, choose colours from your floral fabric. Pull more colours from the floral for your pillows. Love the drapes in the 4th and last photos.

Wow! Great photo's, BettyP. Really drives home the point that chairs don't need to match. I love the shape of the arm chair in the first pic. too. I think it the roll of the arm picks up on the roll in the wood work on my chair. I will look for something like that. And I will go with your sugestion on a stripe as well. Thank you so much every one for helping me with the advice. I don't feel so nervous anymore!

We'd love to see a photo when you are done!