In Illinois, service-based businesses are generally required to obtain state and local licenses and permits. Here are some of the licensing requirements for service-based businesses in Illinois:

1. State licensing: Certain service-based businesses, such as contractors, architects, and engineers, are required to obtain a state license from the Illinois Department of Financial and Professional Regulation (IDFPR).
2. Local licensing: Many cities and municipalities in Illinois require service-based businesses to obtain a local business license or permit. The requirements vary by location, but may include a business registration fee, proof of insurance, and other documentation.
3. Industry-specific licenses: Some service-based businesses, such as barbershops, nail salons, and massage therapists, are required to obtain industry-specific licenses from the state or local government.

For businesses located in Chicago, there may be additional licensing requirements to consider. Here are some of the additional licensing requirements for service-based businesses in Chicago:

1. City of Chicago business license: All businesses operating in the city of Chicago are required to obtain a business license from the City of Chicago. The requirements vary by business type, but may include a license fee, proof of insurance, and other documentation.
2. Professional licensing: Certain service-based businesses, such as attorneys, real estate agents, and accountants, may be required to obtain a professional license from the City of Chicago.
3. Special permits: Depending on the type of service-based business, there may be additional permits or licenses required by the City of Chicago. For example, restaurants may be required to obtain a food service establishment license, and liquor-serving establishments may be required to obtain a liquor license.

It's important for service-based business owners in Illinois and Chicago to be aware of these licensing requirements and ensure that they are in compliance with all applicable laws and regulations. Business owners may want to consult with a qualified business advisor or attorney to ensure that they have obtained all necessary licenses and permits.

For business owners in Chicago, there are several deadlines that exist for state tax forms and tax extensions. Here are some of the most important deadlines to keep in mind:

1. Illinois income tax return: For businesses that operate as pass-through entities (such as S corporations or partnerships), the Illinois income tax return is due on the 15th day of the 3rd month following the end of the tax year (March 15 for calendar-year filers). For businesses that operate as C corporations, the Illinois income tax return is due on the 15th day of the 4th month following the end of the tax year (April 15 for calendar-year filers).
2. Illinois sales tax return: Illinois sales tax returns are due on the 20th day of the month following the end of the reporting period. For most businesses, the reporting period is the calendar month, so the sales tax return is due on the 20th day of the following month.
3. Illinois withholding tax return: Illinois withholding tax returns are due on a semi-weekly, monthly, or quarterly basis, depending on the amount of withholding tax owed. The due date for semi-weekly filers is the Wednesday following the end of the semi-weekly period. The due date for monthly filers is the 15th day of the following month. The due date for quarterly filers is the last day of the month following the end of the quarter.
4. Tax extensions: Business owners in Chicago may request a tax extension for their Illinois income tax return, which will extend the filing deadline by six months. The extension request must be filed by the original due date of the tax return (March 15 for pass-through entities and April 15 for C corporations).

It's important for business owners in Chicago to be aware of these deadlines and ensure that they file all required tax forms and payments on time. Late filings or payments can result in penalties and interest charges. Business owners may want to consult with a qualified tax professional to ensure that they are in compliance with all applicable tax laws and regulations.