Direct synthesis of organo-nitrogen compounds from molecular nitrogen is a challenging subject in the chemistry of nitrogen fixation. Toward this direction, we have long been investigating novel chemical transformations of coordinated dinitrogen. Described herein are our recent results on (1) synthesis of nitrogen-heterocycles from molecular nitrogen via condensation reactions of hydrazido complexes with dialdehydes or their equivalents, (2) bimetallic arylation of molecular nitrogen by using reactions of anionic dinitrogen complexes with eta(6)-fluoroarene complexes, and (3) catalytic silylation of molecular nitrogen.