Connell's attorney, Thomas S. Neuberger, said the suit was filed Friday in Delaware Superior Court.
At a morning news conference, Connell said, "Ammons has destroyed my reputation because of my conservative political and legal beliefs."
Connell, who is white, argues that Ammons, an African American, is angry because Connell used her in violent hypothetical scenarios during class lessons on criminal procedure.
She is accused of making defamatory statements that include attributing racist and sexist remarks to Connell, and at one time characterizing Connell as a threat to the physical safety of the campus community, according to the lawsuit.
Saying she had not seen Connell's suit, Ammons said in a statement Friday, "I have no intention of responding to his allegations in the news media."
In December, Connell, who has taught at the Wilmington school for 26 years, was placed on leave after several students accused him of "discrimination and/or harassment," according to a statement signed by Ammons.
Connell is accused of using hypothetical examples in which he "decided to shoot Dean Ammons and then blew her head off," according to allegations that students made to university officials and that are included in court documents.
Connell conceded that he used Ammons in hypothetical scenarios in which he was a perpetrator who attempted to shoot the dean, but he denied that she was shot in the examples. He called such techniques part of a teacher's academic freedom. "Law professors have sworn under oath in writing to Ammons that my teaching method of poking fun at administrators, black and white, during classroom examples . . . is well-accepted and used nationwide," he said Friday.
Using "quirky hypotheticals," such as the one involving Ammons, "captures students' attention," he said, adding, "Class material can be depressing. It is a way to lighten the atmosphere and help them remember the principles being taught."
In another aspect of the case, students reported that Connell referred to African Americans as "black folk," used excessive profanity, and said, "All criminals are poor, and all poor are black folk."
Connell conceded that he used the term black folk, according to court documents, but denied the other accusations. He also said at the morning news conference he had "no other choice but to sue Ammons" so he could maintain his job, whose health benefits helped cover expenses for a severely disabled 23-year-old daughter in a full-time-care facility.
Later Friday, Connell's attorney issued a short statement about the daughter: "It is my sad duty to report that Molly passed away this afternoon."
University officials say that Connell refused to participate in the college's initial informal investigation of the allegations and that they sought to fire him because his refusal violated his contract, according to university documents included in the lawsuit. Connell declined to participate without an attorney to represent him, the documents say. School regulations say faculty members are entitled to counsel after the procedures reach formal stages.
Last month, a faculty panel recommended that the school withdraw its effort to fire Connell for failing to participate in its hearing. Ammons responded by putting the proceedings on hold. In the meantime, the university will launch another investigation in response to complaints about Connell filed by students.
Contact staff writer Kristin E. Holmes at 610-313-8211