The synthesis of low-coordinate metal ions has been a focus of bioinorganic chemists due to their important roles in active sites in enzymes and protein. Although the isolation of these types of complexes is challenging, porphyrin analogs with one or two carbon atoms in the interior position can be good candidates for generating protected low coordinate metal sites. The metal coordination of one or two carbon substituted hemiporphyrazines, namely monocarbahemiporphyrazine and dicarbahemiporphyrazine, was investigated. These porphyrin analogs, in which one or two of the central metal binding nitrogen atoms were replaced with C-H groups, were synthesized in the early 1950s by Linstead and co-workers, but their metal binding chemistry remained unexplored. Several low coordinate metal complexes of dicarbahemiporphyrazine, namely silver, copper, manganese, iron and cobalt were synthesized. Three different cobalt complexes of monocarbahemiporphyrazine in +2 and +3 oxidation states were also synthesized. Porpholactone is another example of a ring modified porphyrin isomer. In this macrocycle one of the four pyrrollic units is oxidized to an oxazolone ring. Metal complexes of porpholactone may be novel catalysts for epoxidation of alkenes. The synthesis and X-ray crystal structure of first manganese complex of the porpholactone 5,10,15,20-tetraphenylporpholactone are reported. The catalytic activity of the complex by using a variety of substrates was explored and it was compared with that of manganese tetraphenylporphyrin. Metal complexes of a sulfur containing borate-based chelating ligand, tris(imazolyl)borate, HB(mt)3− were examined. Three different modes of interaction were observed with divalent closed d shell metal metal cations: Ca(II), Ba(II) and Hg(II). This study exhibits the diversity of binding not typically observed in the scorpionate family. With group II and group XII metals, the HB(mt)3− ligand can act as a non-coordinating anion, can engage in B-H agostic bonding, and can form metal cluster compounds. Molecular organization of guest molecules within nanometer-sized structures is a big challenge in terms of controlling the physical properties and chemical reactivities. In our group, we are investigating borate-based coordination polymer, lead tetrakis(imidazolyl)borate, to organize and sequester anionic guests. A variety of anionic guests were organized within the layers lead(II) borate scaffolds. The possibility of topochemical polymerization of these pre-organized anionic monomers in the crystalline state was explored.