You can do advanced searches for business registration data on the CTData SOTS Portal for businesses in CT dating back to 1803, and formed as recently as the previous month. Data are updated weekly. 

Use the "Search" dropdown to select the search parameter you think will be most effective, and you can set a date range for when the business was formed (if you know it). Set the business entity type or types, hit the long green search button, and you'll have the results almost immediately. 

On the results page you can click on the business name for more information, or download the results by clicking the gray "Download Results" button at the top of the search results. The business information will be downloaded to your device as a spreadsheet, giving the following information:

• Business name
• Business ID
• Principal
• Agent
• Date formed
• Business entity type
• Street address, city, state and zip code.