Microsoft joined the Android lawsuit club on Friday, accusing Motorola of patent infringements.

A pair of complaints from Microsoft were delivered to the International Trade Commission and in the United States District Court for the Western District of Washington, claiming that Motorola’s Android-based smartphones trample on nine Microsoft patents. The Microsoft technology in question covers tools used for synchronizing e-mail and contacts, scheduling meetings and altering software to changes in battery power and network signal strength, according to a statement.

“We have a responsibility to our customers, partners, and shareholders to safeguard the billions of dollars we invest each year in bringing innovative software products and services to market,” said Horacio Gutierrez, a deputy general counsel at Microsoft, in the statement. “Motorola needs to stop its infringement of our patented inventions in its Android smartphones.”

A Motorola spokeswoman responded that the company had yet to receive a copy of the complaint and thus had no specific comment at this point.

Google brought the open-source Android software into the world, offering it as a platform that companies can customize to suit their various needs. (Here’s a look at how open-source types tend to handle intellectual property issues.)

In March, Apple sued the Taiwanese phone maker HTC, saying its Android phones run afoul of iPhone technology patents. And Oracle sued Google in August, claiming that Android nicked technology found in Java.

Microsoft and HTC entered into an intellectual property accord earlier this year.

Once a proponent of Microsoft’s mobile phone software, Motorola has since gone whole hog with Android. Microsoft has seen its share of the phone market sink with the arrival of the iPhone and myriad Android-based phones.

A number of phone makers are expected to unveil devices based on Microsoft’s new Windows Phone 7 software over the next few weeks.