The prospect of building a soaring new tower was the selling point for an auction last month for some small mid-block properties on Third Ave. between Fifth and Sixth Sts. The buildings formerly included a pizza shop, automotive store and karaoke bar. “They’re selling it with that picture of a big building,” noted Anna Sawaryn of the East Village Community Coalition. “The sign — that’s just telling us what’s going on in this neighborhood.” The real estate broker did not provide information on the buyer, possibly because the deal is not sealed yet. Cooper Union had been trying to buy these properties, but the owner raised the price out of the school’s range. Cooper Union recently sold a lot it owned at the Fifth St. end of the block and still owns the Dolphins restaurant building and parking lot at the Sixth St. end of the block.