The satellite television provider says the lawsuit is an aim to divert attention from Sprint's failure to offer a fair deal to Clearwire shareholders.
Dish Network has ambitions to become a challenger in the home broadband market, but it needs valuable spectrum from Clearwire, Sprint, and LightSquared.
The wireless carrier's lawsuit claims the deal violates shareholder rights and Delaware laws.
Wireless broadband provider's board recommends shareholders accept Dish's bid, which is $1 a share greater than a rival bid by majority owner Sprint Nextel.
Dish's proposal to acquire Clearwire is not "actionable" as certain aspects of it violate Delaware state law, claims Sprint.
Institutional Shareholder Services -- a consultant to mutual funds and other large investors -- says the deal would give Sprint the money it needs to buy spectrum. It remains mum on Dish Network's rival, preliminary offer.
Wireless broadband provider postpones shareholder vote to review Dish's offer, which topped Sprint's by $1 per share.
Satellite TV provider offers $1 a share more than Sprint for the wireless broadband provider, a 29 percent premium over the carrier's offer.
After proxy advisory firm Glass Lewis reiterates that shareholders should vote "no" to an acquisition by Sprint, Clearwire pipes up.
The board urges shareholders to vote "yes" for the bill when they meet to place their ballots on May 31.
"You can take that to the bank," CEO Dan Hesse tells CNET on his sweetened offer for Clearwire.
The carrier's offer is a dime higher than the offer from the satellite provider.