This paper reports on investigating self-sustained volume discharge (SSVD) characteristics in CH3I, C3H7I, C4H9I, CF3I and their mixtures with SF6 and N2, employed as buffer gases, and with O2. The investigations performed in the plane-plane electrode system displaying high electric field edge enhancement have shown that in C3H7I, C4H9I and their mixtures with SF6, N2 and O2 SSVD is realized in the form of a self-initiated volume discharge (SIVD)- SSVD with no any preionization. Addition of SF6 or N2 in C3H7I, C4H9I leads to increasing the discharge stability, the latter being not adversely affected by addition of O2 in amounts of up to 300% of the iodide partial pressure. The fact that SSVD in C3H7I and C4H9I develops in the form of SIVD is indicative of these discharges to be promising for creation of high power pulsed and pulsed-periodic COIL. SIVD has been performed at total mixture pressures of up to 72 Torr and energy depositions of up to 130J/l in a volume of 1.5 l. The performed experimental modeling involving laser geometry of the discharge gap gives firm evidence that SIVD is promise for being used in creation of pulse and pulse-periodic COIL.