770 ILCS 60/9
If payment shall not be made to the contractor having a lien by virtue of this act of any amount due when the same becomes due, then such contractor may bring suit to enforce his lien in the circuit court in the county where the improvement is located, and in the event that the contract relates to two or more buildings or two or more lots or tracts of land, then all of said buildings and lots or tracts of land may be included in one complaint. Any two or more persons having liens on the same property may join in bringing such suit, setting forth their respective rights in their complaint; all lien claimants not made parties thereto may upon filing a petition to intervene become defendants and enforce their liens by counterclaim against all the parties to the suit; and the complaint shall not thereafter be dismissed as to any lien claimant, or as to the owner or owners of the premises without the consent of such lien claimant. The plaintiff and all defendants to such complaint may contest each other's right without any formal issue of record made up between them other than that shown upon the original complaint, as well with respect to the amount due as to the right to the benefit of the lien claimed: Provided, that if by such contest by co-defendants any lien claimants be taken by surprise, the court may, in its discretion, as to such claim, grant a continuance. The court may render judgment against any party summoned and failing to appear, as in other cases of default. Such suit shall be commenced or counterclaim filed within two years after the completion of the contract, or completion of the extra or additional work, or furnishing of extra or additional material thereunder.
770 ILCS 60/9