Despite breakthroughs in MAS NMR hardware and experimental methodologies making large biological systems accessible for atomic-level characterization, sensitivity remains a major challenge. Here, we report dramatic, 3-4 fold, sensitivity enhancements, in heteronuclear-detected experiments using a novel CPMAS probe, where the sample coil and the electronics operate at cryogenic temperatures, while the sample is maintained at ambient temperatures (CPMAS CryoProbeTM). While this technology is mature for solution NMR applications, it has not been available for triple resonance MAS NMR experiments until very recently, with the introduction of the Bruker BioSolids CryoProbeTM. The benefits of BioSolids CryoProbeTM-based experiments are discussed for assemblies of the HIV-1 capsid protein and for kinesin/microtubule assemblies – systems that are challenging to study using conventional MAS NMR probes. The sensitivity gains afforded by this technology have permitted the acquisition of outstanding-quality 2D and 3D homo- and heteronuclear correlation spectra, as well as of single-scan 2D 13C-13C correlation spectra. Multidimensional data of this sort is otherwise inaccessible for such complex systems, even at high magnetic fields, due to intrinsically low sensitivity and the resulting prohibitively long experiment times. Data sets acquired with the BioSolids CryoProbeTM contain signals that are not otherwise detectable and which enable resonance assignments for the systems studied. We present further analysis of the sensitivity and resolution in these data sets. We envision that this probe technology is applicable to a wide range of systems and particularly beneficial for large biological assemblies with intrinsically low sensitivity.