These days, the hottest fashion accessory may well be your smartphone — not just which model you carry, but also how you dress it up.

The nation’s largest electronics retailer recently realized it was lacking in the latter department, so now it is making a big investment to remedy the situation.

Best Buy Co. Inc. on Wednesday will announce three new collaborations with well-known designers — Nanette Lepore, Anna Sui, and Isaac Mizrahi New York — on exclusive lines of colorful, floral, and striped cases for smartphones, tablets and laptops. The tech accessories will be available for preorder on its website and will hit stores Oct. 5. A couple of weeks ago, Best Buy launched a similar collection with Kate Spade New York.

While such designer partnerships have become fairly common at department stores and mass merchandisers, Best Buy officials say it’s a “first of its kind” for them.

“We know that women are excited about the technology,” said Mary Ortizcazarin, vice president of accessories for the Richfield-based retailer. “But we clearly had some gaps in our assortment.”

While Best Buy offers a deep selection in the newest gadgets, its offerings when it comes to accessories has been more of a ho-hum affair with a sea of black and blue cases. Meanwhile, many apparel stores have been peddling more colorful, fashionable tech accessories for a while now.

“Why would the number one consumers electronics retailer not have them as well?” Ortizcazarin added.

With this new line of products, Best Buy is tapping into a growing market. According to the research firm NPD Group, sales of smartphone cases have grown 7 percent in the last year to about $2.4 billion.

Ben Arnold, an NPD analyst, noted that smartphones have become a staple of the masses, with about two-thirds of U.S. households having one.

“So you have to start making accessories that appeal to moms,” he said.

Not only that, but women are more likely than men to own multiple smartphone cases. Some fashionistas, particularly those among the millennial crowd, even like to change them out to match their outfits.

Expect to see more designer partnerships as smartwatches and other wearables grow in popularity, Arnold added.

There are already some other examples. Tory Burch has a line of accessories for Fitbit. And Diane von Furstenberg has teamed up with Google Glass on a line of stylish eyeglasses.

“It’s an everyday reality that women are trading fashion dollars for technology. They’re deciding whether they want that designer dress or the new iPhone,” said Carol Spieckerman, president of retail consulting firm Newmarketbuilders. “That’s another reason Best Buy is smart to do this.”

The collaboration is also a way for Best Buy to offer something unique at a time when the gadgets themselves are often widely available through many retailers. “It’s very difficult in consumer electronics to have exclusive products,” she said. “So then it’s always a race to the bottom on price.”

But Best Buy doesn’t have to worry about price-matching or showrooming with these items. And they will likely be an easy sell with a high margin to boot.

“They are take-and-go items,” she said. “There’s no assembly, no delivery.”

The new line of products have been in the works for about six months. The Anna Sui and Nanette Lepore collections were developed with the help of the Council of Fashion Designers of America. The designers’ share of proceeds from those two lines will go back toward to the council to help fund scholarships and other initiatives.

Best Buy reached out to the council for suggestions on designers with whom it might make sense to team up. It then narrowed the list to a couple of designers.

“Several, if not all of them will be recognized” by Best Buy shoppers, said Ortizcazarin. But even if customers don’t know these names, “They will quickly understand who they are and the credibility they have within the designer world.”

Minneapolis-based Established Brands helped Best Buy figure out the production and logistics of the partnerships.

The tech accessories will get an eye-popping display in the mobile area of Best Buy stores. The items range in price from $29.99 to $39.99.

While executives hope they will be a hit as holiday gifts, they are planning to keep them around well beyond that.

“It’s not just for holiday,” said Ortizcazarin. “We are committed to having a designer line at Best Buy.”