Interstellar dust is a key component of galactic ecosystem, as well as a redistributor of light. Great uncertainties still remain, however, about properties of dust, especially in environments substantially different from those in the Galactic disk and in the Magellanic Clouds. I will talk about several ongoing research projects and ideas of probing dust emission and/or attenuation in such extreme environments as the Galactic center and in high-z extreme starburst galaxies.