Triplet thymine is well known as a hotspot for DNA photo damage, and a reference experiments value for its energy has been inferred experimentally [1]. This average value may blur a DNA sequence dependence which can be revealed by ad hoc simulations. Beyond the isolated thymine which has been much studied [2], the dynamics of triplet thymine in a B-helix has been less investigated computationally. We have investigated owing to QM/MM-MD simulations which highlight the interaction mode of DNA-drug for a large range of photosensitizers [3,4] including benzophenone. Based on these structures, we can map the triplet-triplet energy transfer in short oligonucleotides relying on static QM/MM schemes. We also investigate in situ the impact of micro hydration in tuning photoproperties of a luminescent DNA probe [5] relying on non-adiabatic dynamics. In the future, we plan to investigate the action of photosensitizers with nucleosome core particles for which the mechanical and electrostatic embedding differ from B-DNA.