NSF's vision for a Cyberinfrastructure Framework for 21st Century Science and Engineering (CIF21) considers an integrated, scalable, and sustainable cyberinfrastructure as crucial for innovation in science and engineering (see www.nsf.gov/cif21). The Data Infrastructure Building Blocks (DIBBs) program is an integral part of CIF21. The DIBBs program encourages development of robust and shared data-centric cyberinfrastructure capabilities to accelerate interdisciplinary and collaborative research in areas of inquiry stimulated by data.Effective solutions will bring together cyberinfrastructure expertise and domain researchers, to ensure that the resulting cyberinfrastructure components address the researchers' data needs. The activities should address the data challenges arising in a disciplinary or cross-disciplinary context. (Throughout this solicitation, ‘community' refers to a group of researchers interested in solving one or more linked scientific questions, while ‘domains' and ‘disciplines' refer to areas of expertise or application).This solicitation includes two classes of awards:Pilot Demonstration Awards, andEarly Implementation Awards. The Pilot Demonstration projects should address broad community needs of interest either to a large number of researchers within a research domain, or extending beyond that to encompass other disciplines. Early Implementation projects are expected to be of interest to multiple research communities in multiple scientific and engineering domains; these projects will develop frameworks that provide consistency or commonality of design across communities, ensuring that existing conventions and practices are appropriately recognized and integrated, and, most importantly, that the real needs of the community are identified and met. Prospective PIs should be aware that DIBBS is a multi-directorate activity, and are encouraged to submit proposals with broad, interdisciplinary interest. PIs are encouraged to refer to NSF core program descriptions, Dear Colleague Letters, and recently posted initiatives on directorate and divisional home pages to gain insight as to the priorities for the relevant area(s) of science and engineering in which their proposal may be responsive. It is strongly recommended that prospective PIs contact a program officer from the list of Cognizant Program Officers in the organization(s) closest to the major disciplinary impact of the proposed work to ascertain that the scientific focus and budget of the proposed work are appropriate for this solicitation.