As a field of study, optics have been a critical to the development of material’s science. The interaction between light and matter is often non-destructive and non-invasive; making it powerful in the determination of materials’ compositions, and their properties at the electronic and vibrational levels. In the present work, we have broadened the use of light spectroscopy as a technique to determine, accurately, mechanical and thermal properties of molecular systems. More specifically, pressure (P) and temperature (T)-dependent Raman spectroscopy allowed us to access elusive mechanical (Young’s modulus (E), Grüneisen parameter (γ), and mechanical strain (ε)) and thermal properties (coefficient of thermal expansion (α), specific heat capacity (c_v), and thermal strain (ε_T)) of linear carbon chains (LCCs), which are one-atom thick linear carbon molecules. The results show that all these quantities follow universal relations that are solely dependent on P, T, and on the number of carbon atoms (N). In Appendix 01 we also describe how spectral derivative analysis combined with absorption and photo-luminescence spectroscopies allowed for unravelling elusive electronic and vibronic transition in free base 5,10,15,20-meso-tetra(pyridyl)-21H,23H-porphyrin (H2TPyP).