Are there any grantee relationship management systems that focus on centralizing communication and document sharing?

Yes. A number of grantee relationship management platforms are built specifically to centralize communication, document sharing, and collaboration between funders and grantees. Common examples include:

• Blackbaud Grantmaking – strong for grant workflows, document storage, and grantee communications.
• SmartSimple Cloud for Grants Management – highly configurable, with portals for grantees to upload documents and communicate in one place.
• Submittable – often used for grant applications and ongoing grantee interactions, including file sharing and messaging.
• Fluxx Grantmaker – centralizes grant records, communication, approvals, and document exchange.
• Foundant GLM + Grantseeker / CommunitySuite – includes applicant/grantee portals and document management.
• Salesforce-based grant management solutions – many nonprofits and foundations build relationship management and communication workflows on Salesforce.

If your main priority is ongoing relationship management rather than just application processing, look for features like:

• shared portal for grantees
• threaded messaging or secure communications
• document upload/version control
• activity history and notes
• permission controls and audit trail
• reminders and task tracking

If you want, I can also give you:

1. a shortlist by organization size,
2. a comparison table, or
3. recommendations specifically for foundations, government grantmakers, or nonprofits.