[en] With the recent discovery of in-plane chemically ordered MAX phases (i-MAX) of the general formula ()₂ AC comes addition of non-traditional MAX phase elements. In the present study, we use density functional theory calculations to investigate the electronic structure, bonding nature, and mechanical properties of the novel (W_2/3Sc_1/3)₂AlC and (W_2/3Y_1/3)₂AlC i-MAX phases. From analysis of the electronic structure and projected crystal orbital Hamilton populations, we show that the metallic i-MAX phases have significant hybridization between W and C, as well as Sc(Y) and C states, indicative of strong covalent bonding. Substitution of Sc for Y (M ²) leads to reduced bonding strength for W–C and Al–Al interactions while M ²–C and M ²–Al interactions are strengthened. We also compare the Voigt–Reuss–Hill bulk, shear, and Young’s moduli along the series of M ¹  =  Cr, Mo, and W, and relate these trends to the bonding interactions. Furthermore, we find overall larger moduli for Sc-based i-MAX phases. (paper)