Conn. Gen. Stat. § 31-90

Any person, and any agent or officer of any corporation, who coerces or compels, or attempts to coerce or compel, any laborer, mechanic or other employee in the employ of such person or corporation to agree that, as a condition of retaining his position as such employee, he will not join any labor organization, shall be fined not more than two hundred dollars or be imprisoned not more than six months or both.