GuideStar Pro This link opens in a new windowGuideStar Pro is a database of all 501(c) tax-exempt organizations registered with the IRS, providing contact details, mission statements, financial data, and leadership information. While it does not include grant listings, it helps funders and researchers verify nonprofits. GuideStar Pro includes Charity Check, a tool for confirming an organization’s eligibility to receive tax-deductible contributions. Access is available on-campus only.