In The Development Of Modern Coordination Chemistry, Mononuclear Complexes Were Studied In Detail, During The Last Century. It Is Only Over The Past 30 Years That Special Attention Has Been Devoted On Properly Designed Multinuclear Systems Which Would Provide New Reactivity Patterns And Physical Properties That Could Not Be Achieved With Related Mononuclear Complexes. New Synthesis Of Such Complexes In Relation To Rare Coordination Patterns And Bioinorganic Model Chemistry Lead To Investigate Novel Structural, Magnetic And Spectral Aspects. The Monoxime And Amino Ethanolate Ligand Based Ni4 ‘Star Shaped’ Complexes Have Synthesized Which Adopt Rare Inverse 12-MC-4 Metallacrown Core Structure. A ‘Butterfly’ Ni4, Ni2 And Mono Nickel Complexes Are Also Obtained By The Coordination Of Monoximate And Different Exogenous Ligand Following A Similar Synthetic Strategy. A Novel Group Of Ni6, Cu4, Co4 And Cu2 Complexes Have Explored Using Simple Phenolate Bridging Bis-Tridentate Ligand System. The Solvent And Exogenous Bridge Dependent Courses Of Both Descend And Ascend Of Ni4 To Ni1 And Co1 To Co3 Complexes Have Been Studied. Reaction Course Dependent Hydrolytic Cleavage Of Central Imidazolidinyl Ring And Stabilization Of Imidazolidinyl Phenolate Ring In The Mono And Binuclear Complexes Of Co, Ni And Cu. Our Approach Was To Produce Multinuclear Coordination Complexes With Groups Of Multidentate Ligands. Magnetic Properties Were Interpreted As A Function Of Structural Feature And Presence Of Different Coligands. Keywords: Active Sites; Exogenous; Endogenous; Self-Assembly; Oximate; Amino Ethanolate; Metallacrown; Butterfly; Bis-Tridentate; Phenolate; Tetracubane; Azide Bridging; Hexanickel; Doublecubane; Cubane; Tetracopper; Heterometallic; 8-Quinolinolate; Mixed Valence; Tricobalt; Metallacycle; Imidazolidinyl; Chain; Dicopper; X-Ray Structure; Molar Susceptibility; Magnetic Properties.