personal property taxes are not deductible for Illinois taxes (if they are business-related they should be deducted on the business form). Only real estate taxes on your principal residence and it's a credit of 5% of the RET. Complete form ICR. Illinois has several limitations as to the credit. if income is too high it's zero, if any is allocable to a business only the nonbusiness portion is eligible for the credit. you must timely pay the taxes
