The interaction of galaxies is known to regulate the star-formation activities in the merging systems, or galaxy pairs, however, whether and how such interactions affect the central supermassive black hole, often manifested as active galactic nuclei---AGNs, is still under debate.
Controversies exist as to whether AGN activities are enhanced or suppressed during the different merging phases.
The answer to this question involves understanding of the physical properties of galaxy pairs in various scales, from the supermassive black hole at the galactic center to dust and gas of various phases---ionized, molecular, and atomic---throughout the galaxies and in the close vicinity. In this talk I will review some recent progresses made with IR-bright galaxies, and the combination of
observations of significantly different scales
and resolutions
to connect AGNs and star formation activities in mergers, including new insights
from JWST and FAST observations.
