HTC, the smartphone maker behind T-Mobile's G1 'Google phone', has bought San Francisco-based One & Co, a design company it worked with on the development of the HTC Touch Diamond.

One & Co will retain its name and continue to serve other clients, HTC said. Previous One & Co customers include Nike, K2, Sony, Timex and Microsoft.

T-Mobile G1 review

Apple iPhone review

Smartphone makers are relying more heavily on designers in a bid to emulate the success of Apple's iPhone, according to Satoshi Nakajima, who spent more than a decade at Microsoft, started software platform developer UIEvolution and most recently started up iPhone application developer Big Canvas.

"This is just one piece, but if they want to build something similar or better to the iPhone, development needs to be driven by someone from industrial design," he said. "To compete ... they need to have some designer at the head of the mobile division and let that person be fully in charge."