The　prime　motive　of　this　disquisition　is　to　deal　with　mathematical　analysis　of　natural　convection　energy　transport　driven　by　combined　buoyancy　effects　of　thermal　and　solutal　diffusion　in　a　trapezoidal　enclosure.　Casson　fluid　rheological　constitutive　model　depicting　attributes　of　viscoelastic　liquids　is　envisioned.　The　influence　of　the　inclined　magnetic　field　governed　by　Lorentz　field　law　is　also　considered.　To　raise　the　essence　of　the　presently　used　computational　and　physical　domain,　an　innovative　structural　design　called　fillet　is　capitalized　at　the　edges　of　the　cavity.　A　numerical　solution　of　the　leading　formulation　is　sought　through　Galerkin　finite　element　dis-cretization.　Momentum,　temperature,　and　concentration　equations　are　interpolated　by　quadratic　polynomials,　whereas　pressure　distribution　is　approximated　by　a　linear　interpolating　function.　Domain　discretized　version　is　evaluated　in　view　of　triangular　and　rectangular　elements.　Newton＇s　scheme　is　employed　to　resolve　the　non　-linearly　discretized　system　and　a　matrix　factorization-based　non-linear　solver　renowned　as　PARADISO　is　used.　Validation　of　results　is　ascertained　by　forming　an　agreement　with　existing　studies.　Streamlines,　isothermal　and　iso　concentration　contours　patterns　are　portrayed　to　evaluate　variation　inflow　distributions.　Kinetic　energy,　local　heat,　and　mass　fluxes　are　also　divulged　in　graphical　and　tabular　formats.