2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/6825Millimetre-band scans of the frequency space towards optically dim quasars is potentially a highly efficient method for detecting new high redshift molecular absorption systems. Here we describe scans towards 7 quasars over wide bandwidths (up to 23 GHz) with sensitivity limits sufficient to detect the 4 redshifted absorbers already known. With wider frequency bands, highly efficient searches of large numbers of possibly obscured objects will yield many new molecular absorbers.3 pages, conference proceedings to appear in Highlights of Astronomy, ASP (IAU XXV JD21, The Astrochemistry of External Galaxies)Astrophysicstext