This thesis comprises two independent parts. With an estimated 40 million people currently living with HIV-1 and the flagship treatment regimen, antiretroviral therapy (ART), facing challenges such as it’s inability to eradicate the disease thereby necessitating lifelong dependence on treatment, there exists a need for a novel class of drugs that can address the shortcomings presented by the currently approved therapeutics. CD4 mimetic compounds (CD4mcs) are small molecules that mimic the host’s natural HIV-1 receptor, CD4, and are able to bind to the CD4 binding site of the envelope glycoprotein (Env) to induce premature and irreversible conformational changes that inactivates the virus. Furthermore, these conformational changes leave the Env vulnerable to neutralization via antibody dependent cellular cytotoxicity (ADCC) rendering this as an avenue for a potentially curative therapeutic. In the first part of this thesis, the development indoline based CD4mcs are investigated by modifying various regions of the scaffold to form better interactions with the gp120 binding pocket. This structure-activity relationship (SAR) study was guided by in silico predictions and evaluated by X-ray crystallography and in vitro assays. The second part of this thesis is about the identification and development of a novel class of compounds used to inhibit SARS-CoV-2 entry. It is no secret the impacts that COVID-19 had on society, while there are dozens of authorized drugs and treatment options each one of them comes with shortcomings, especially as the virus evolved to the Omicron variant. As such even today, there exists a need for additional therapeutics. Our group repurposed a compound, VE607, that was identified as a SARS-CoV entry inhibitor and discovered that it showed activity against SARS-CoV-2. Thereafter, our work has been dedicated to the elaboration of this scaffold to ascertain its mechanism of action as well as to develop it further as a preclinical candidate. The work presented in this part involves the systematic modification of VE607 that resulted in a more potent analog that we were able to advance to in vivo studies.