"I am so overdressed!" exclaims Mary-Kate Olsen, in a heavy black sculpted leather Givenchy jacket, on a surprisingly hot New York City day this past spring. Perched behind a massive desk next to her equally stylish (and pint-size) sister Ashley in their design studio, Mary-Kate fiddles with her iPad, eventually deciding on a little Led Zeppelin for some inspiration. It's not often that one of these two makes a fashion misstep, but this time it's with good reason: "We took the red-eye in from Los Angeles last night. We're exhausted," they explain in unison, both armed with organic green juices for an energy boost.

Such an arduous schedule is nothing new for the ambitious entrepreneurs, who started in the entertainment business at a mere nine months old and have slowly built up an impressive fashion empire. The jewel in the crown is their high-end line, The Row, under which they are launching a set of sophisticated bags that will hit stores at the end of July.

Ashley elaborates on their vision for the debut: "We wanted there to be multiple options in the collection so you aren't stuck with one style; there's a purpose to every bag." Hence the names. There's the Day Luxe (a structured top-handle tote), the Classic Shoulder (a long-strap messenger), the Metal Frame (need we say more?), and four other iterations in fine finishes, including ostrich, alligator, and lizard, which will be sold at Barneys New York and specialty boutiques like A'maree's. Our favorite? The aptly named Twin Mini, a petite cross-body bag that features different skins on each side, for a chic two-in-one component.

These arbiters of cool simply understand what women want. "We didn't want too much branding; we didn't want an It bag," says Mary-Kate of the new line. What they did want was a set of accessories that would perfectly complement their fall runway collection, a luxe grouping of statement coats in sumptuous furs and rich hues as well as pared-down separates in a crisp, neutral palette.

Their decision to delve into the accessories market was only natural. "We are such bag people," says Ashley. Over the years, by being photographed with a slew of designer carryalls, they've catapulted them into the mainstream. Case in point: Mary-Kate was one of the first to step out carrying Alexander Wang's black pebbled duffel with a gold-studded bottom, making it an instant must-have. It's inevitable that their own line will follow suit. Jokes Ashley: "I've ordered every version for myself!"