To understand the effect of concentration on the ground state absorption, concentration dependent (10-100 M) absorption studies were performed for complexes 1-3 and L ((Figure , figure ) in DMF under ambient conditions. For compounds 1, 2 and L an increase in absorption intensity at 392 nm was observed with no additional absorption band at the lower energies, thus suggesting the absence of intermolecular - interactions in the complexes and ligand. However, for complex 3 an increase in concentration lead to the appearance of a new lower energy absorption band between 450-550 nm (Figure ). Such appearance of a new lower energy absorption band in LMCT transition from the  orbital of iodine to the p orbital of bismuth. Therefore, the observation of the lower energy band in the concentration dependent studies of 3 in DMF can be clearly assigned to transitions taking place in the inorganic part of the complex. While in case of 1 and 2, no lower energy band extending up to ~550 nm was observed due to the comparatively weaker electron donating tendency of the chlorine and bromine based complexes, hence weaker electronic transitions from halogens are involved in the 1 and 2. However, the absorption spectrum of BiBr3 shows a lower energy band (Figure ) between the 345-410 nm which corresponds to the mixture of LMCT ( orbital of bromine to p orbital of bismuth atom) and sp transition while in BiCl3 only the tail of lower energy interconfigurational sp transition is observed. To further confirm the observations in complex 3, we designed and synthesized a new complex 4 (Figure ) with weaker electron donating methyl groups attached to phenanthroline. The absorption studies for complex 4 at different concentrations (10-100 M) were repeated in DMF (Figure ). Similar to complex 3, a new broad absorption band was observed between 410-500 nm for complex 4 (Figure , Figure ) upon increasing the concentration. The comparison of absorption spectra between complexes 3, 4 and BiI3 (Figure ) shows that a lower energy band is observed in all compounds thus confirming that the lower energy band originates from the inorganic BiI3 part of the complexes rather than from - stacking or similar non-covalent interactions. Finally, the absorption studies of 1, 2, 3 and 4 confirm that the lower energy band at 392 nm is composed of multiple transitions involving different parts of the complexes. In complex 1 the absorption at 392 nm consists of a metal centered sp transition, intra-organic ligand transition and transition between metal and ligand, while in complex 3, the lower energy absorption band mainly involves transitions from the bismuth center (sp), weak LMCT (halogen to metal), intraorganic ligand transition and transition between metal and ligand. In complex 3 and 4 the absorption bands at 392 nm and 410-500 nm are due to the transition of organic ligand, bismuth atom, between metal and organic ligand, and strongly from the ancillary ligand iodine to the bismuth center. The comparative studies of all the complexes with the inorganic salts also confirms that the ground state electronic properties are strongly influenced by the inorganic part in bioctahedron based coordination complexes.