Wedding outfit recipes are listed below.

[Outfit for female characters]
・Lilac  Corsage
  Crafting Skill:  Clothcraft
  Necessary Crystal:  Wind Crystal or Cyclone Crystal
  Necessary Materials: Silk Cloth, Spider Web, Lilac, Twinthread

・Opaline  Dress
  Crafting Skill:  Clothcraft
  Necessary Crystal:  Light Crystal or Aurora Crystal
  Necessary Materials: Rainbow Thread, Velvet Cloth, 3 Silk Cloths, Rainbow Cloth, 2 Twinthreads

・Opaline  Hose
  Crafting Skill:  Clothcraft
  Necessary Crystal:  Light Crystal or Aurora Crystal
  Necessary Materials: 3 Silk Threads, 2 Velvet Cloths, 2 Twinthreads

・Opaline  Boots
  Crafting Skill: Leathercraft, Clothcraft
  Necessary Crystal:  Light Crystal or Aurora Crystal
  Necessary Materials: Rainbow Thread, Silk Cloth, Rainbow Cloth, 2 Sheep Leathers, Manticore Lth., Twinthread

[Outfit for male characters]
・Argent  Coat
  Crafting Skill:  Clothcraft, Leathercraft, Alchemy
  Necessary Crystal:  Light Crystal or Aurora Crystal
  Necessary Materials: Silver Chain, Silver Thread, Velvet Cloth, Silk Cloth, Eltoro Leather, Galateia, Baking Soda, Platinum Silk

・Argent  Hose
  Crafting Skill:  Clothcraft, Leathercraft, Alchemy
  Necessary Crystal:  Light Crystal or Aurora Crystal
  Necessary Materials: Silver Chain, 2 Velvet Cloths, 2 Sheep Leathers, Eltoro Leather,  Baking Soda,  Platinum Silk

*You can engrave your name on the wedding outfits if you use Cyclone Crystal or Aurora Crystal in place of Wind Crystal or Light Crystal

These outfits can also be purchased from the Matrimonial Coffer for those who may have difficulty synthesizing them.

[Matrimonial Coffer and Celebratory Chest]
http://support.eu.square-enix.com/faqarticle.php?kid=51794&ret=main&id=455&la=2