The search for new magnetic materials with better thermal and magnetic performance led to the discovery of new intermetallic phases, R(Fe, M)12 and R3(Fe, M)29 which are known as 1:12, and 3:29 compounds. In both the compounds, the presence of a third element M (=Ti, V, Cr, Mn, Mo, W) is necessary for the stabilization of the phase. This article discusses recent investigations of structural and magnetic properties of substitutionally and interstitially modified 2:17 and 3:29 compounds.