(a) A typical Raman spectrum of a mammalian cell (on glass slides) depicting the crowded fingerprint region, the C-H stretch region, and the cell-silent region (pink). (b) Relative Raman peak intensities of common silent-region Raman tags (i.e. C≡C, C≡N and C-D). Adapted in part with permission from ref 64. Copyright 2010 American Chemical Society. (c) Representative triple-bond tagged small metabolites and drugs. (d) SRS Imaging targeting the alkyne vibrations for incorporation of thymidine-analogue EdU in live HeLa cells, choline-analogue propargylcholine in live neurons, glucose-analogue 3-OPG in cultured mouse brain tissue slices (Scale bar: 40 μm) and alkyne-tagged ferrostatin in live HT-1080 cells. Other scale bars: 10 μm. Adapted in part with permission from ref32, Copyright 2014 Nature publishing group. Adapted in part with permission from ref65, Copyright 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Adapted in part with permission from ref59. Copyright 2018 American Chemical Society. (e) 13C isotope editing enables three-color imaging of EdU, EU and 17-ODYA with alkyne probes. Scale bar, 25 μm. Adapted in part with permission from ref61. Copyright 2014 American Chemical Society. (f) Representative small molecules with deuterium tagging. (g) SRS imaging targeting the C-D vibration for the incorporation of deuterated amino acids in live HeLa cells, d31-palmitic acid in melanoma cells (Scale bar: 20 μm) and d8-PG in the mice stratum corneum at the depth of 12 μm after 124 min of treatment. Adapted in part with permission from ref66, Copyright 2013 United States National Academy of Sciences. Adapted in part with permission from ref29, Copyright 2020 Nature publishing group. Adapted in part with permission from ref67. Copyright 2014 American Chemical Society. (h) SRS imaging of d5-Gln-labeled mHtt-97Q aggregates in live HeLa cells. Quantifications for the local polyQ concentrations within the aggregates are also shown. Scale bar: 10 μm. Adapted in part with permission from ref68. Copyright 2020 American Chemical Society. (i) C-D and triple-bond enriched polymer dots with amplified Raman signals. Adapted in part with permission from ref69. Copyright 2017 The Royal Society of Chemistry.