Reference voltage source using classic rectifier diodes
A silicon diode has a negative temperature coefficient of about -2mV/°C, so a 10°C change in temperature will result in about a 3% shift in your "reference". The forward voltage is also not all that well specified and is fairly dependent on current (which also means that loading the reference will change the voltage). If none of those things bothers you, have at it. It's been done. 

A better idea is to use a three terminal regulator perhaps with a voltage divider and buffer. It will draw a few mA \$I_q\$, but will be much more stable than a series string of diodes. 

Low voltage (like less than 5V) Zener diodes are not very good (very soft "knee"), so I would avoid them. 

Incidentally, should you have a defunct PC power supply kicking around, they typically have an LM431 shunt voltage reference in them (on the side isolated from the mains), and it's usually not what fails.