This is BoShek, smuggler extraordinaire and the man who introduced the greatest Star Wars couple: Obi-Wan Kenobi and Chewbacca. As a keen eye for fashion might note, he is appropriately dressed in some sort of spacesuit, making him look like a much more competent spacefarer than Han Solo and his always-billowing shirt. One movie later, we meet Bossk, a ruthless bounty hunter in the employ of Lord Vader. Opting for the more daring mustard yellow version, he is sporting the same casual-but-cool short-sleeved space suit as BoShek.
As it turns out, both dastardly criminals stole their fashion sense from the rebel's A-Wing pilots, who wear this snazzy getup as their official uniform.