The rapid progress of perovskite solar cells (PSCs) with a current power conversion efficiency (PCE) near to 27%[1] is mainly attributed to the optimization of optoelectronic properties of the perovskite layer and the interfacial engineering of the charge-selective contacts. Among several strategies, the use of self-assembled molecules (SAMs) as selective charge transport layers has attracted interest owing to their potential to improve charge extraction, suppress non-radiative recombination, and minimize current leakage, which results in enhanced efficiency and stability of devices [2]. In this work, we have synthesized and characterized four dipodal indolocarbazole SAMs, used as hole-selective contacts in inverted PSCs based on the CsFAMA perovskite absorber (Eg = 1.6 eV). We investigate the effects of SAMs' structural variations, such as methoxy substitution in terminal functional groups and the length of alkyl spacers, on interfacial properties and device performance. To do so, the ITO/SAM and ITO/SAM/PSCs interfaces were characterized in detail. The results reveal the effects of indolocarbazole SAMs on the crystallization of the perovskite and charge dynamics in the devices. The resulting iPSCs showed PCEs between 19.76% and 22.20%, with fill factor exceeding 82% and good stability under continuous illumination. Notably, iPSCs using SAM with unsubstituted indolocarbazole and pentyl spacer (5CPICZ) exhibited the highest PCE of 22.20%. In contrast, devices using analogous SAMs with propyl spacers (3CPICZ) achieved a PCE of 22.01%. On the other hand, the iPSCs with methoxy-substituted SAMs showed reduced performance. Devices with SAM 3CPICZ-M (methoxy groups and propyl spacers) achieve a PCE of 21.51%, %, while those with SAM 5CPICZ-M (methoxy groups and pentyl spacers) yielded 19.76%. The observed PCE trend is attributed to the electronic and structural differences caused by the functional groups and spacer length. The experimental results reveal that, compared to their methoxy-substituted counterparts, the unsubstituted CPICZ SAMs more effectively passivate interfacial defects, reducing nonradiative recombination, leading to improved PCE. Transient optoelectronic measurements demonstrated that improved PCE in devices with unsubstituted CPICZ SAMs is owing to longer carrier lifetimes and reduced charge recombination [3]. The improved energy level alignment, enhanced hole mobility, charge transfer dynamics, longer carrier lifetime, and suppressed bimolecular/trap-assisted recombination all contribute to the highest performance of 5CPICZ-based devices. Overall, this study highlights the importance of molecular design and provides a pathway for developing efficient indolocarbazole-based SAMs for perovskite solar cell applications.