First, chitin was reacted with 4,5-dichlorophthalic acid and diphenic acid, and thus two new chitin derivatives (C45DA and CDA) were synthesized. Then, C45DA and CDA were characterized by various spectroscopies and techniques (FTIR, ¹³C CP-MAS solid-state NMR, XRPD, SEM, and TGA/DTA). Besides, some electrical properties of C45DA were measured. After the characterization process, the Schottky diodes of C45DA and CDA were made. It was determined that these diodes showed photodiode characteristics at the same time. Later on, both electrical properties (ϕ_b, n, and R_s) and photoelectrical properties (I _Illumination/I _Dark, I _SC, and V _OC) of these diodes were determined.