Various 3-pyrrolines (2,5-dihydropyrroles) have been synthesized by two-step reaction sequence of alkylation/alkylidene carbene CH-insertion reaction. Synthesis of 3-pyrroline has been reported by employing cis-1,4-dichloro-2-butene as starting reagent. 3-Pyrroline is a heterocyclic building block. The excited state dynamics of 3-pyrroline by Hamiltonian model based on the vibronic coupling model has been investigated. Trifluoromethylated azomethine ylide is reported as precursor for the synthesis of 3-pyrroline building blocks. 3-Pyrrolines are reported as highly useful intermediates for the synthesis of functionalized pyrrolines, pyrrolidines and other natural products. Preparation of 3-pyrroline(2,5-dihydro-1H-pyrrole) from (Z)-1,4-dichloro-2-butene, via Delépine Reaction has been reported. It is formed as intermediate in the synthesis of N-(tert-butyloxycarbonyl)-3-pyrroline. Reaction of Me3Al and Me3Ga with 3-pyrroline is reported.