Descubri la solucion, gracias al foro de mathworks, dejo escrito el codigo x si alguien se ve apurado:
GUI_1:
function pushbutton_Callback(hObject, eventdata, handles)
gui2; %it returns GUI_2
waitfor(gui2);
load('acept_cancel.mat');
if b_Acept
set(handles.pushbutton2,'BackgroundColor',[0 1 0]); %green colour
%else, it keeps the default grey colour
end
GUI_2:
function pushbutton1_Callback(hObject, eventdata, handles)
%Button ACEPT
b_Acept= true;
save('datas.mat');
save('acept_cancel.mat',b_Acept);
close;
function pushbutton2_Callback(hObject, eventdata, handles)
%Button CANCEL
b_Acept= false;
save('acept_cancel.mat',b_Acept);
close;
salu2
