This paper introduces a new genus Delonicicola, to accommodate D. siamense sp. nov., which was found associated with Delonix regia seed pods, collected in Chiang Rai Province, Thailand. ITS sequence data confirmed a close relationship of Delonicicola with Liberomyces and Asteromella in Xylariomycetidae. Phylogenetic and molecular clock analyses of combined LSU, SSU and RPB2 sequence data provide evidence for a new family Delonicicolaceae and a new order Delonicicolales in Xylariomycetidae. Members of Delonicicolaceae are saprobes, endophytes or pathogens of angiosperms and it is characterized by pseudostromatal immersed, papillate ascomata, short pedicellate asci with a simple apex and 1-septate, hyaline ascospores. The asexual morph is coelomycetous with pycnidial conidiomata and allantoid, filiform or bacilloid, hyaline conidia.