While existing literature has primarily focused on carbene-stabilized amino- and arylborylenes of the form [(carbene)BR] (R = substituent), herein we report the generation and metallomimetic reactivity of the first carbene-stabilized alkylborylene [(CAACMe)BCy] (CAACMe = 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene, Cy = cyclohexyl. Furthermore, the transition metal-like decarbonylation reactions of a borylene complex, [(CAACMe)BCy(CO)], derived from borylene [(CAACMe)BCy] and CO, are described. Additional findings described include (i) the identification of the coordination stages of the ligand to boron towards forming complexes [(CAACMe)BCyL] in the reduction route from starting material [(CAACMe)BCyBr2] and in the photolysis route from carbonyl complex [(CAACMe)BCy(CO], and (ii) insights from quantum-chemical computations regarding the molecular and electronic structure of the borylene at various stages.