I. Direct observation of o-xylylene (o-quinodimethane) in solution, Dimerization kinetics of some o-quinodimethanes; II. Kinetic and product studies on the dimerization of [alpha]-methyl-substituted o-quinodimethanes; III. Direct observation of 1,2-napthoquinodimethane and 9,10-phenanthroquinodimethane, Dimerization kinetics of resonance-stabilized o-quinodimethanes