65 ILCS 5/9-2-70
The assignee of a special assessment lien may, not later than 5 years after the date of the sale and assignment of the special assessment lien by the municipality, file a complaint to foreclose the lien. The lien of a special assessment which has been assigned and any right of action to foreclose the same shall not expire during the pendency of a proceeding to foreclose the lien commenced within 5 years from the date of the sale and assignment of the lien by the municipality. If no action is commenced within 5 years from the date the lien is assigned by the municipality, the lien and all right of action to enforce the same shall expire and cease to exist.
The assignee of a special assessment lien sold or assigned on or prior to December 31, 1957 may, not later than 5 years after the effective date of this amendatory Act of 1975, file a complaint to foreclose the lien. The lien of a special assessment which has been assigned and any right of action to foreclose the same shall not expire during the pendency of a proceeding to foreclose the lien commenced within 5 years after the effective date of this amendatory Act of 1975. If no action is commenced within 5 years, the lien and all right of action to enforce the same shall expire and cease to exist.
65 ILCS 5/9-2-70