Conn. Gen. Stat. § 12-600: Taxes to be paid before instituting action on tax in court.

Any taxes, penalties or interest due from any company under the provisions of sections 12-587 to 12-602, inclusive, shall be paid in full before any action may be instituted in any state court to challenge all or any part of the provisions of said sections. No injunction or restraining order shall be issued by any state court to stay or prevent the imposition or collection of taxes as provided under said sections.