1. Illinois Income Tax Act (IITA)
  2. IITA Section $201(k)$ (Research and Development Credit)
  3. 35 ILCS $5/201(k)$
  4. Illinois Department of Revenue (IDOR)
  5. Schedule 1299-C (Income Tax Subtractions and Credits for Individuals)
  6. Schedule 1299-D (Income Tax Credits for Corporations and Fiduciaries)
  7. Schedule 1299-I (Income Tax Credits Information and Worksheets)
  8. Credit Code 5340 (R&D Credit)
  9. Qualifying Expenditures (for increasing research activities)
  10. Internal Revenue Code (IRC) Section 41
  11. Qualified Research Expenses (QREs)
  12. Research Conducted in this State (Illinois)
  13. Base Amount (for R&D calculation)
  14. Average Qualifying Expenditures (3 preceding tax years)
  15. Credit Percentage (6.5%)
  16. Nonrefundable Credit
  17. Carryforward Period (5 Years)
  18. Forfeited Credit
  19. In-House Research Expenses
  20. Contract Research Expenses
  21. Basic Research Payments (IRC $\S 41(e)$)
  22. Wages for Qualified Services
  23. Cost of Supplies
  24. Rental or Lease Costs of Computers
  25. Qualified Research (IRC $\S 41(d)$ Four-Part Test)
  26. Process of Experimentation
  27. Technological in Nature
  28. Elimination of Uncertainty
  29. Business Component
  30. New or Improved Function, Performance, Reliability, or Quality
  31. Exclusion: Research After Commercial Production
  32. Exclusion: Adaptation of Existing Component (Customer Need)
  33. Exclusion: Duplication of an Existing Product or Process
  34. Exclusion: Surveys or Studies
  35. Exclusion: Research on Internal-Use Computer Software
  36. Exclusion: Research Outside Illinois
  37. Exclusion: Research in Social Sciences, Arts, or Humanities
  38. Exclusion: Government-Funded Research
  39. Distributive Share of Credit
  40. Pass-Through Entities (Partnerships, S corporations, LLCs)
  41. Partnership’s or S corporation’s Schedule K-1-P
  42. IITA Section $201(a)$ and $(b)$ (Tax Imposed)
  43. IITA Section $201(c)$ and $(d)$ (Personal Property Tax Replacement Income Tax)
  44. Taxable Year
  45. Unused Credit
  46. Unitary Taxpayer/Group
  47. Written Agreement (for credit distribution by S Corps/Partnerships, post-2023)
  48. Public Act 103-0595 (R&D credit extension to 12/31/2031)
  49. Quantum Information Science Research and Development Tax Credit
  50. Qualifying Quantum Information Science Expenditures