Can a corporation contribute after the end of its fiscal year and still claim the credit on its prior fiscal year tax return?

No. Corporations can only claim their contribution in the tax year in which the contribution is made (plus, five years for carry forward purposes). The law allows your corporation to allocate your tax liability to a School Tuition Organization (STO) such as STO4KIDZ, designating a private school, not a specific student. However, if there are not enough eligible students at your designated school, the money will be awarded among eligible students attending other qualifying private schools in Arizona.