Nanosized　materials　are　known　to　have　the　ability　to　withstand　ultralarge　elastic　strains　(4-10%)　and　to　have　ultrahigh　strengths　approaching　their　theoretical　limits.　However,　it　is　a　long-standing　challenge　to　harnessing　their　exceptional　intrinsic　mechanical　properties　in　bulk　forms.　This　is　commonly　known　as　＂the　valley　of　death＂　in　nanocomposite　design.　In　2013,　a　breakthrough　was　made　to　overcome　this　challenge　by　using　a　martensitic　phase　transforming　matrix　to　create　a　composite　in　which　ultralarge　elastic　lattice　strains　up　to　6.7%　are　achieved　in　Nb　nanoribbons　embedded　in　it.　This　breakthrough　was　enabled　by　a　novel　concept　of　phase　transformation　assisted　lattice　strain　matching　between　the　uniform　ultralarge　elastic　strains　(4-10%)　of　nanomaterials　and　the　uniform　crystallographic　lattice　distortion　strains　(4-10%)　of　the　martensitic　phase　transformation　of　the　matrix.　This　novel　concept　has　opened　new　opportunities　for　developing　materials　of　exceptional　mechanical　properties　or　enhanced　functional　properties　that　are　not　possible　before.　The　work　in　progress　in　this　research　over　the　past　six　years　is　reported.