Didymocarpus cordatus is one of the larger Gesneriads in Peninsular Malaysia, growing to about 1 m tall. The large ovate leaves with unequal base and toothed margin grow to about 20 by 10 cm. Its inflorescence is a lax, many-branched cymes and bears up to 50 flowers. The small bell-shaped flowers are pale lilac, with dark purple spots outside when in bud.

This species is a taxonomic riddle. Initially, it was described as a species of Didymocarpus in 1845 (de Candolle) but when Ridley revised the Flora of Malay Peninsula (Ridley, 1925), he transferred it to Paraboea. This species was confirmed as a Didymocarpus species when the genus concept of a few Malesian genera was redefined (Weber & Burtt, 1998[1997]), but its affinity with the grouping within the genus was still uncertain. A recent molecular phylogenetic study (Palee et al. 2006) confirms its placement within Didymocarpus. They suggested its affinity to section Didymocarpus, but mentioned it is without strong statistical support.

Didymocarpus cordatus is widely distributed in the mountains of Peninsular Malaysia such as Gunung Jerai (Kedah Peak), Bukit Larut (Maxwell Hill) and Gunung Ledang (Mount Ophir) at 600–1000 m elevation above sea level. It is one of a few Peninsular Malaysian Gesneriads that also occurs in Sumatra, Indonesia.