Actually, donations or charitable contributions made to a qualified organization, from the checking account of the S Corporations cannot reduce the S corporation taxable income directly. This is because charitable contributions are part of those special items of deductions that flows through to the individual owners K-1.
The K-1 will include the charitable contribution allocable to that individual shareholder (based on the individual shareholders percentage ownership) that would be deductible on that individual's 1040 tax return.
Thus, the contributions made to charity will flow directly to the individual shareholders or members of the S corporation. These deductions would be included on Schedule A itemized deductions under charitable contributions.