The NSF Division of Advanced Cyberinfrastructure (ACI), formerly known as the Office of Cyberinfrastructure, is interested in encouraging collaborations with China-based researchers who are currently funded by or seeking funding from the National Natural Science Foundation of China (NSFC). This interest is one outcome from the US and China Workshop Series to Build a Collaborative Framework for Developing Shared Software Infrastructure, which was supported jointly by the NSF and the NSFC (workshop website: http://www.nsf-nsfc-sw.org/), and builds on a previous Dear Colleague Letter (NSF 12-096). US-based researchers can submit proposals that involve collaboration with China-based researchers who are currently funded by or seeking funding from the National Natural Science Foundation of China (NSFC) to the Software Infrastructure for Sustained Innovation (SI2) cross-cutting program (NSF 13-525) led by ACI. Interested investigators MUST contact the SI2 lead program officer prior to submission. Any submission must include a letter from the proposed Chinese collaborator and the proposal or award number of the NSFC-funded project on which they are supported.