Abstarct: Delbar mextamorphic-igneous complex is located in 150 Km away of Southeast Shahrood, 40 Km away of Southeast Biarjomand in the northern margin of Central Iran structural zone. The complex with age of about 550 to 600 million years old (late Neoproterozoic- Early Cambrian) has been cut by three series of basic- intermediate dikes including Precambrian gabbrodioritic dikes, Middle Jurassic gabbroic dikes and Oligomiocene basaltic dikes. In this study, the features of the field, petrography, geochemistry and petrography of gabbroic and basaltic dikes have been investigated. Gabbroic dikes in addition to the Delbar mextamorphic-igneous complex, have cut the low- grade mextamorphics (greenschist facies) of the Lower Jurassic, but they have not intruded in the middle- Upper Jurassic and Lower Cretaceous sediments. Therefore, baxsed on the field studies, the Middle Jurassic age has been considered for them, which is consistent with the their radiometric age (152±35 million years ago). Basaltic dikes also have been cut the Precambrian mextamorphic units, Lower Cretaceous limestones and Lower Oligocene red marls (Lower Red Formation) and then, the age of Oligomiocene have been considered for them. baxsed on the petrographical studies, plagioclase and clinopyroxene (augite) are the main minerals forming the gabbroic dikes. The minor minerals includ apatite and magnetite and the secondary minerals mainly consist of sericite, amphibole (due to uralitization of clinopyroxene), chlorite and prehnite. The most important textures of the gabbroic dikes include intergranular, ophitic,subophitic and sieve. Clinopyroxene (augite to titanaugite), plagioclase and olivine are the main minerals forming the basaltic dikes. Minor minerals include magnetite, and the secondary minerals include zeolite, analcime, Iddingsite, bulangite and calcite. Fluidal microlitic porphyry and hyalomicrolitic porphyry, glomeroporphyric and amygdaloidal textures are the most important textures in these rocks. baxsed on the geochemical studies, Jurassic gabbroic dikes have subalkaline and Oligomiocene basaltic dikes have alkaline nature. In the chondrite normalized diagrams the gabbroic and basaltic dikes show enrichments in LREEs relative to HREEs. This enrichment can be justified by low degrees of partial melting of the mantle source or crustal contamination. baxsed on the petrological studies, the magma forming of the gabbroic dikes have been generated by 7- 20% partial melting of an enriched spinel lherzolitic mantle source in depths less than 80 Km and magma forming of the basaltic dikes have been generated by 5% partial melting of an enriched garnet lherzolitic mantle source in depths of 105 to 110 Km. Temporal and spatial position and geochemical and petrological characteristics of the gabbroic and basaltic dikes suggests that they have been formed in the back-arc extensional basins caused by oblique subduction of the Neotethys oceanic lithosphere beneath central Iran continental lithosphere in Middle Jurassic and Oligomiocene times respectively.