Monolith was first used as a material for chromatographic separation two decades ago and solid-phase extraction over 10 years, and since then, separation science has undergone a dramatic change owing to advancements in analytical technology. Recently, monolith has been modified to suit various devices for the extraction and enrichment of analytes in any matrices of environmental, food, and biological analyses. This approach has contributed to miniaturization and automation for sample preparation, and it can reduce the time and cost requirements of sample preparation. Recently, numerous applications have been demonstrated for online and inline preconcentration coupled with monolith, and many kinds of devices have been designed and developed for offline devices. In this review, these applications and devices are listed and discussed in reference to other fields.