begin{align}
foo &=mydiagram{text{width width}}       & bar &= mydiagram{text{width width width}}
\[jot]
foo &=mydiagram{text{width width width}} & bar &= mydiagram{text{width}}
end{align}

defmydiagram#1{%
    begin{CD}
        S^{{mathcal{W}}_Lambda}otimes T
        @>j>>
        T\
        @V{#1}VV
        @VV{End P}V\
        (Sotimes T)/I
        @=
        (Zotimes T)/J
    end{CD}%
}

documentclass[a4paper,11pt]{article}

usepackage{amsmath}
usepackage{amscd}

DeclareMathOperator{End}{End}

defmydiagram#1{%
    begin{CD}
        S^{{mathcal{W}}_Lambda}otimes T
        @>j>>
        T\
        @V{#1}VV
        @VV{End P}V\
        (Sotimes T)/I
        @=
        (Zotimes T)/J
    end{CD}%
}

begin{document}

begin{align*}
foo &=mydiagram{text{width width}}       & bar &= mydiagram{text{width width width}}
\[jot]
foo &=mydiagram{text{width width width}} & bar &= mydiagram{text{width}}
end{align*}

end{document}