Thermoelectric (TE) materials and the devices based on TE materials have been considered as one of the smartest approaches to reduce global energy consumption by recovering the wasted heat from various heat sources and converting it into electricity. The series of Zintl phases adopting the Ca₁₄AlSb₁₁-type structure has been known for their promising thermoelectric properties at high temperatures and leading to many worldwide researches. In this work, we have successfully synthesized two novel quinary compounds belonging to the Yb_14-xCa_xAl_1-yMn_ySb₁₁ system by using the molten Sn-metal flux method. The isotypic crystal structures of the title compounds were characterized by both powder and single-crystal X-ray diffractions, and those crystallized the Ca₁₄AlSb₁₁-type structure with the tetragonal space group I4₁ (Z = 8, Pearson Code tI208). According to the SXRD refinement results, the four symmetrically independent cationic sites contain different mixed occupations of Yb and Ca. Moreover, those cations display a certain site preference, which can be explained by either the site-factor or the electronic-factor. A series of theoretical calculations using tight-binding linear muffin-tin orbital method was also performed to understand the overall electronic structures as well as the QVAL value of each atomic site. These values can provide the rationale for the observed site preference based on the electronegativity of each atom.