Chickpea (Cicer arietinum L.) is an important proteinacious food crop. Ascochyta rabiei (Pass.) Lab. is the major biotic factor that limits chickpea productivity worldwide by causing blight disease. It causes 20-25% yield loss in chickpea annually, however, it may cause total crop failure under epidemic conditions. The most important control measure of this disease is cultivation of resistant varieties, but the resistance does not last long. Chemical control is also effective but it leads to health hazards. The alternative way to control the chickpea blight is the use of natural products and their synthetic analogues. The present study was, therefore, designed to identify natural antifungal compounds from two allelopathic tree species namely Syzgium cumini (L.) Skeels and Eucalyptus citriodora Hook for the management of A. rabiei. In screening bioassays, in vitro antifungal potential of methanolic leaf, fruit, stem-bark and root-bark extracts of S. cumini and E. citriodora was evaluated against A. rabiei. Different concentrations of these extracts ranging from 0.5% to 4.0% were evaluated against the fungal pathogen. In these laboratory bioassays, extracts of various parts of both the trees species exhibited variable antifungal activity. Leaf extract of E. citriodora and fruit extract of S. cumini exhibited the best antifungal activities against the target fungal pathogen resulting in 71–95% and 44–46% reduction in fungal biomass. These extracts were subjected to further bioassays guided fraction using various chromatographic and spectroscopic techniques. Three kilograms dried and crushed leaves of each of E. citriodora and fruits of S. cumini were extracted with methanol. The solvent was evaporated on a rotary evaporator and the crude methanolic extracts were partitioned using n-hexane, chloroform, ethyl acetate and n-butanol in increasing order of solvent polarity. Different concentrations (1. 562, 3.125, 6.25, 12.5, 25, 50, 100, 200 mg mL-1) of these four organic solvent fractions were tested in vitro against the fungal pathogen. Different fractions of methanolic leaf extract of E. citriodora and fruit extract of S. cumini exhibited pronounced antifungal activities resulting in 30–93% and 22–66% reduction in fungal biomass over control, respectively. Chloroform fractions of methanolic leaf extract of E. citriodora and fruit extract of S. cumini were selected for isolation of effective antifungal constituents using thin layer chromatography (TLC), preparative thin layer chromatography (PTLC) and high performance liquid chromatography (HPLC). Four compounds namely ethyl iso-allocholate (1), oxime-, methoxy-phenyl (2), heptacosane (3) and octadecane (4) were identified through GC-MS in chloroform fraction of methanolic fruit extract of S. cumini. Likewise, three compounds namely 3-cyclohexene- 1-ol, 4- methyl-1-(1-methylethyl)- (5), 1-cyclohexene- 1-carboxaldehyde, 4-(1-methylethyl)- (6), and eucalyptol (7) were identified in chloroform fraction of methanolic leaf extract of E. citriodora. Results of the present study indicate that both the allelopathic tree species possess substantial antifungal properties against A. rabiei. Especially, compounds present in chloroform fractions of methanolic leaf extract of E. citriodora and fruit extract of S. cumini are highly active against the target fungal pathogen. After further screening, structures of the most potent antifungal constituents from the seven isolated compounds in the present study can be used as analogues for the preparation of nature friendly fungicide to control one of the most destructive fungal pathogens of chickpea