http://www.arts…

according to the color wheel, reds or purples would look fantastic.

to match green you can use caramel brown or light brown...orange looks good though so it can match green with brightness

lighter shades of brown or tan for both.

Since I don't know the shade of green it's hard to pick a color to match. I would, however, choose a fabric you like for the chairs first. If the sofa is solid, choose a small pattern with green in it for one chair and a plaid or stripe with the same colors for the other. Usually you can find fabrics that coordinate in color perfectly with different patterns on them, and this looks more original and interesting than having them the same. Once you do that, choose a color from your fabric to paint.
For example, one chair could be covered in this:
http://www.beau…
and the other in this:
http://www.beau…
Then you could paint the walls a soft sandy shade with an accent wall of cinnamon!

Are you planning on reupholstering or using slip covers? Covers will be way cheaper. I think that browns and beige go great with green, very relaxing. You can add color in the accessories, golden yellows, red, blue, just about any color you like. Green is the color of nature. How about a mural on the wall? It could open the whole space up. Good luck!

play around with the Sherwin Williams color visualizer to find something that you like. It is the best paint visualizer on the web, imho. I like how their color palette is laid out, I like that you can search by color family & color name, the "painted" rooms look the most realistic, and it suggests coordinating color schemes. You can literally spend hours:
http://www.sher…

I think a brown like "pottery urn" (# 7715) would make a terrific accent wall color, and then a nice gold, brick red, or burnt orange fabric for chairs.