[2] The genus is distinguished by its black, pear-shaped fruiting bodies (perithecia) with large, nipple-shaped ostioles that have a granular surface, and a dark, multi-layered wall made up of hyphal cells forming a pseudoparenchymatous structure.

The genus was circumscribed in 2014 by the lichenologists Javier Etayo and Pieter van den Boom, with Zwackhiomacromyces constrictocarpus assigned as the type species.

The wall of the ascomata is dark and multi-layered, made up of hyphal cells that form a pseudoparenchymatous structure, with the outermost layer sometimes having granulose extracellular pigment.

[3] The asci (spore-producing cells) of Zwackhiomacromyces are elongated and club-shaped, with a thickened wall on the side and at the tip, where an ocular chamber is present.

While the genus is generally uniform in terms of its hamathecial structures, asci, and ascospores, variations do exist in some species, such as Zwackhiomyces lecanorae with its simple spores and Zwackhiomyces cervinae, which features spores with a perispore and a tendency to turn brown.