For Men
The brief is pretty simple – black tie means you’re to wear a black bow tie and/or vest with your dinner jacket or a tuxedo. If desired, men may wear a white dinner jacket with their black tuxedo trousers. Another option would be a dark-coloured suit (e.g., navy, charcoal, dark grey)
For Women
A floor-length dress in an evening-appropriate fabric, such as velvet, chiffon, silk, or lace, is the best bet. A formal dress or an elegant, floor-length pantsuit is also appropriate. Note that floor-length is required.
See some ideas to get started below: