The aims is to characterizing the gas and dust properties prior to and in the neighborhood of active intermediate- to high-mass star formation. Two Infrared Dark Clouds (IRDCs), IRDC 19175-4 and IRDC 19175-5, that are located in the vicinity of the luminous massive star-forming region IRAS 19175+1357, but that remain absorption features up to 70um wavelength, were observed with the Plateau de Bure Interferometer in the 3.23mm dust continuum as well as the N2H^+^(1-0) and ^13^CS(2-1) line emission.