There is no higher magic necessary, just transcribe into the canonical first-order system, encode the boundary conditions, make a reasonable initial guess of the solution shape and call the BVP solver
Pr = 5
F,dF,ddF,θ,dθ = u
return [dF, ddF, θ-0.25/Pr*(2*dF*dF-3*F*ddF), dθ, 0.75*F*dθ]
def bcs(u0,u1): return [u0, u0, u1-1, ...
What does differentiating the first equation once to give $\theta'$ and twice for $\theta''$ and plugging into the second equation to give a single equation for $F$ give? Seems like solving a single equation for $F$ might be your best approach (or vice versa).