Ten derivatives of 2-borabicyclo[1.1.0]but-1(3)-ene (1a-1j) with different degrees of frustration have been investigated using density functional theory. Moreover, 1a-1j as Lewis bases were used to form Lewis adducts C3X2BYH/B(C6F5)(3) (2a-2j) with Lewis acid B(C6F5)(3). Optimized geometries and the thermodynamic properties of giving the Lewis adducts C3X2BYH/B(C6F5)(3) reveal that 2a-2j are frustrated Lewis pairs (FLPs). Their reactivity of activating H-2 and HF show that 2a-2j are unfavorable to heterolytically cleave H-2, whereas 2c-2j can cleave HF to form [C3X2BYH](+)[FB(C6F5)(3)](-). In addition, we found the structures of [C3X2BYH](+) in [C3X2BYH](+)[FB(C6F5)(3)](-) contained a planar tetracoordinate carbon (ptC). Therefore, a new method of obtaining main group element compounds with ptC by using FLPs was presented.