Semicrystalline iPP is a commodity polymer, with several crystalline modifications, like the monoclinic α-, the trigonal β- and the othorombic γ-modification. iPP crystallizes into α-form under conventional processing conditions. The modification of crystalline structure al-lows the flexible tuning of mechanical and optical properties of this commodity polymer, which is the key of its dynamic development. Special additive called nucleating agents are used for this purpose in the industrial practice. Most of the nucleating agents induce the for-mation of the α-modification, but several additives nucleate the formation of β-modification. The β-nucleating agents can be either completely selective to the β-modification like Ca-suberate and Ca-Pimelate, or may have dual nucleating ability resulting in mixed polymorphic composition like N,N’-dicyclohexyl-2,6-naphthalene-dicarboxamide. In fact most of the β-nucleating agents available recently have dual nucleating ability thus the polymorphic structure formed in their presence depends predominantly on the conditions of crystallization. Moreover, both α- and β-nucleating agents developed recently are often partially soluble in iPP in order to ease their dispersibility in the polymer melt during processing. Therefore the structure form in the presence of a soluble nucleating agent with dual ability depends both on the recrystallization condition of the nucleating agent as well as the thermal conditions like melt temperature and cooling rate. The aim of this work is the detailed characterization of the crystallization process and the structure formed in the presence of these soluble nucleating agents. The crystallization process was studied by calorimetry (DSC) and the supermolecular structure was studied by polarized optical microscopy (POM) and scanning electron microscopy (SEM).