With the next generation of radio interferometers/SKA pathfinders, we expect to uncover a large number of HI, as well as the very rare OH, absorption systems at redshifts of $z\leq 1$. These can be used to address many important issues such as measuring baryonic content of the Universe, probing large-scale structure and galaxy evolution, as well as obtaining independent measurements of various combinations of fundamental constants at look-back times of up to 7.7 Gyr. Here we summarise our recent results regarding just where we expect the HI and OH absorption systems to be found:

1. HI in absorbers intervening distant quasars - how from the geometry of a flat expanding Universe we expect a large detection rate at $z\leq 1$.

2. HI absorption associated with the host galaxy/quasar - we show that the optical selection of these objects, particularly at high redshift, greatly reduces the 21-cm detection rate. Blind surveys are therefore expected to improve significantly on current detection rates.

3. OH absorption - how through colour selection we expect to significantly increase the number of redshifted OH absorbers above the paltry five currently known. Again, the pursuit of the dimmest objects, through blind surveys, being the best strategies.