You aren't attending a wedding or presidential ball. You are going to a singles dance. Wear what you would normally wear when you like to go out on the weekend to look nice. Some men like to wear a jacket although it isn't necessary. A pair of dress pants or nice jeans and a collared shirt will do just fine.
Most women wear anything they like.
Pants Suit, jeans, skirt, dress. You know how it is with you women. Your closet is packed with clothes but you don't have a thing to wear.