Sure. Mullein has been used either by being carried or smoked by multiple cultures. The leaves have actually been used as part of Ceremony of certain Native American tribes such as the Navajo and Hopi (mainly to be brought back to center or to remove maddness). It would actually be added the pipes along with other herbs to help initiate the shamanic travel while still keeping the individual grounded. The Greeks would be carried the herb to protect themselves from magic. In England it was mixed with salt and dill to be sprinkled on properties to repel baneful sprints. As far as more modern practices, it is used as a substitute for graveyard dirt to help attract spirits of the dead. It is also is used as a tea to help ailments of the lungs, especially the flowers.
Catnip has connections with Native American tribes as well, such as the Cherokee, mainly for its medicinal properties. It is known for relaxing the body but was also viewed as a tonic for strength when made into a tea. As far as magic goes, it is often associated with luck, courage and love. I would recommend only a small pinch or so as it can give you a headache if you use too much. I actually used it to help with moving on from smoking marijuana when I had to get clean for a new job but was on edge.
Edit: I would recommend smoking this either just before or during the evocation or meditation