In this seminar I will present results from time-dependent density functional theory (TDDFT) simulations in real time, where the coupling of the Kohn-Sham Hamiltonian with classical force-fields or with a Tight-Binding (TB) approach provide multiscale treatments to tackle large molecular or condensed phase systems. In particular, the integration of TDDFT with a TB Hamiltonian allows to model quantum transport across molecules immobilized between massive electrodes. On the other hand, hybrid QM-MM Ehrenfest dynamics are used to describe photoisomerization or photodissociation of organics in solution.