Viridian Dacnis is found solely in northwestern Colombia and in adjacent eastern Panama. This species generally is considered to be rare, although historical records suggest that it formerly was locally common. Viridian Dacnis currently is treated as Near Threatened according to IUCN criteria. Viridian Dacnis is sympatric with two other species of Dacnis, the much more widespread Blue Dacnis (Dacnis cayana), and the more localized Scarlet-thighed Dacnis (Dacnis venusta), both of which are more numerous than Viridian. Both also should be readily distinguished from the generally very pale-colored Viridian Dacnis, which lacks a black throat in the male, and females are entirely green over the head, and both sexes of Viridian have pale irides. Viridian Dacnis is primarily found in forest, but also visits edges and even nearby scrub.
The name "Viridian" derives from the Latin word viridis, meaning green (Humez and Humez 1987), and this greenish color is also referenced in the Spanish common name Dacnis Verdoso (Hilty 2011, de Juana et al. 2012). Dacnis is derived from the Greek word daknis, an unidentified type of bird from Egypt mentioned by Pompeius Festus and Hesychius (Jobling 2010). The specific epithet viguieri honors Dr. Camille Viguier, a French zoologist and collector, who first discovered the species in the coast Gulf of Darién (Salvin and Godman 1883, Jobling 2010).