This study comprehensively examines the synthesis, characterization, and application of two distinct orthoborate photodiodes: K S r S m B O 3 2 and K C a S m B O 3 2 under varying illumination intensities. The selection of K S r S m B O 3 2 and K C a S m B O 3 2 as active materials is predicated on their exceptional optical and electrical properties. Structural characterization of the synthesized molecules was performed using FT-IR spectroscopy, P-XRD, ICP-MS, TGA/DTA, and SEM-EDX methodologies. The growth of the K S r S m B O 3 2 and K C a S m B O 3 2 borate compounds was achieved via the spin coating technique on n-Si substrates. Performance evaluation of the fabricated Al/ K S r S m B O 3 2 / S i and Al/ K C a S m B O 3 2 / S i heterojunction photodiodes involved comprehensive current-voltage (I-V) and current-time (I-t) measurements. Key performance indicators such as photocurrent, photosensitivity (K), responsivity (R), and specific detectivity (D*) were assessed to evaluate the photodiodes efficiency in photodetection applications. The findings reveal that the Al/ K C a S m B O 3 2 / S i photodiode exhibits superior performance across multiple parameters compared to its Al/ K S r S m B O 3 2 / S i counterpart. Furthermore, the Al/ K C a S m B O 3 2 / S i photodiode exhibits enhanced detectivity, underscoring its capability to effectively detect weak signals across various lighting conditions. The study concludes that optimizing the composition and structural properties of these orthoborate photodiodes can lead to significant advancements in their functionality and reliability for diverse optoelectronic applications.