The traditional party look
When you are heading at a business party, you can give yourself a new look without overdoing it. For that you can wear a black men's suit jacket with a nice dress pant and you are all set. You can accessorize the look with a nice pocket watch. For shoes you can pick up smart wingtips.
However, if you want, you also get the italian dinner jacket in any other solid color. Whatever you wear you must be sure that it looks really good. For instance, you can create a matching look for the business party. Wear a maroon dinner jacket along with maroon trouser and a white shirt.