Dust grains play a crucial role in many physical and chemical processes in the interstellar medium (ISM) and in protoplanetary disks (PPDs). In the ISM, dust properties influence, for example, the formation and temperature of the major molecules in molecular clouds. It is therefore important to characterise the grain size, structure, shape and material composition in all phases of the ISM. Observations of the dust SED and extinction give indication of the dust properties and how these properties change towards denser regions. Compared to the diffuse ISM the observed SEDs of these denser regions show a decrease in colour temperature, increase in spectral index and increase in emissivity at 250 μm. Based on the THEMIS dust model, these observations can be explained self-consistently with coagulation and accretion processes of dust in regions with Av<16. These evolutionary processes can also explain the observed core- and cloud-shine. In conclusion, the evolutionary processes and especially grain growth begins in denser regions of the ISM. The dynamics of PPDs depend on the chemistry and ionisation rate of the disk which is influenced by the abundance and properties of dust particles. Assuming different approaches to calculate the X-ray (and UV) ionisation rate and different chemical reaction networks including dust particles, the electron abundance and subsequently the Elsasser number are derived. The calculations show that non-ideal magnetohydrodynamic effects dominate the disk interior in the early stage of the disk and that dust growth and dust settling can lead to turbulences in the disk. The calculations further show that dust settling is strongly dependent on the properties of the dust particles.